API Index (APIX): A Global Discovery Infrastructure for Autonomous Agent Services

1.1.1. Motivation: A Concrete Origin

The API Index was not conceived in the abstract. It emerged from a concrete practical failure.¶

A buying bot was built for a private use case: monitoring online shops for a specific product and purchasing it automatically the moment it became available. This is a straightforward task for an autonomous agent — exactly the kind of task agents are well-suited for.¶

The bot failed, not because the task was technically complex, but because the internet's infrastructure is actively hostile to it:¶

HTML-only product pages. Product availability, price, and purchase state were encoded in HTML rendered for a human eye. No machine-readable API existed. The bot had to parse HTML — fragile, maintenance-intensive, and broken by every redesign.¶

Cloudflare Bot Management and equivalent shields. The majority of commercial web services now sit behind bot mitigation infrastructure. Cloudflare Bot Management, and equivalent products from Akamai, Imperva, and others, are deployed specifically to detect and block non-human request patterns. Repeated automated requests — even at modest frequency — trigger rate limiting, CAPTCHA challenges, or silent blocking. A buying bot that polls a product page to detect availability is treated identically to a malicious scraper or a DDoS participant.¶

CAPTCHA payment barriers. Even when product pages were reachable, payment flows required solving CAPTCHAs that explicitly excluded non-human actors. The purchasing step — the final, necessary action — was deliberately made inaccessible to the bot.¶

Proxy network pollution. To work around rate limits and bot detection, the bot required a rotating proxy network — different IP addresses on each request to disguise its automated origin. This is not a solution: it pollutes internet traffic with avoidable requests, raises the cost of operation, and contributes directly to the adversarial dynamic between bots and infrastructure operators. Every proxy request is a wasted roundtrip that a machine-readable API endpoint would have made unnecessary.¶

Polling as the only state-change mechanism. Because the bot had no way to subscribe to product availability events, it had to poll the product page continuously. This is architecturally wasteful: the bot consumes server resources and network bandwidth to repeatedly ask a question whose answer has not changed. If the service had provided a notification registration endpoint — a webhook, a server-sent event stream, or a WebSocket channel — the bot could subscribe once and receive a push notification when the product became available. No polling. No proxy network. No CAPTCHA exposure.¶

These are not edge cases. They are the standard experience for any autonomous agent attempting to consume a commercial internet service today. The buying bot illustrates why the API Index is necessary: not as an academic exercise, but as the infrastructure layer that makes autonomous agents functional participants in the commercial internet.¶

1.1.2. The Discovery Problem

When an autonomous agent must fulfill a task that requires an external service, it faces a fundamental discovery problem: how does it find services that can fulfill its requirement?¶

Current approaches are inadequate:¶

• Hardcoded URLs: brittle, require human maintenance, do not adapt to new or changed services.¶

• LLM training data: stale, non-authoritative, not machine-verifiable.¶

• Human-curated lists: do not scale, not machine-navigable, lack structured metadata.¶

• Web search: returns HTML documents designed for humans, not structured service descriptions for agents.¶

What is needed is a machine-native equivalent of a search engine: a global, always-current, structured index of services that autonomous agents can query by capability, trust level, liveness, and other machine-relevant criteria.¶

1.1.3. Lessons from Prior Art

The APIX is not the first attempt at a global service registry. Prior efforts must be understood explicitly so that their failure modes are not repeated.¶

UDDI (Universal Description, Discovery and Integration)
UDDI was a SOAP-era standard for a global service registry with the same conceptual goal as APIX, published as an OASIS Committee Draft in October 2004 (editors: Clement, Hately, von Riegen, Rogers). It failed for three reasons: (1) extreme complexity of the XML-based data model; (2) no automatic verification — all data was self-asserted with no crawling or validation; (3) no adoption incentive — there was no commercial model to sustain registration or discovery. APIX addresses all three directly: a simple JSON manifest, automated spider verification, and a commercial tier model.¶

robots.txt (Robots Exclusion Protocol)
Machine-readable, but concerned with exclusion — telling crawlers what not to access — not with discovery of capabilities. Per-domain only. Not a registry.¶

MCP (Model Context Protocol)
Defines tool and capability descriptions for LLM-based agents. Excellent for consumption once a server URL is known. Does not address the discovery problem: there is no index of MCP servers. APIX is complementary to MCP — it can index MCP servers as one supported spec type.¶

Well-Known URIs (RFC 8615)
Per-domain machine-readable metadata at /.well-known/. Useful for per-service metadata but requires the consumer to already know the domain. No cross-service search or global index.¶

DNS
DNS resolves names to addresses but carries no capability semantics. It is an architectural analogy for APIX's federation model, not a comparable system.¶

1.1.4. Related IETF and W3C Work

As of April 2026, the number of Internet-Drafts working in adjacent areas of agent/bot infrastructure has grown significantly. None addresses the same problem as APIX. This section documents each and states the relationship explicitly.¶

draft-pioli-agent-discovery (ARDP — Agent Registration and Discovery Protocol)
Proposes a federated agent registration and discovery protocol. Agents self-register capabilities (MCP, A2A, HTTP, gRPC) with federated resolvers. Deliberately decentralised — no global registry mandate, no central query URL. Relationship to APIX: complementary. ARDP addresses agent-to-agent capability advertisement within a federation. APIX addresses global, cross-organisation service discovery from a neutral central index. The APM spec.type vocabulary could reference ARDP-registered agents as a future extension.¶

draft-narajala-courtney-ansv2 (ANS v2 — Agent Name Service v2)
Full title: "Agent Name Service v2 (ANS): A Domain-Anchored Trust Layer for Autonomous AI Agent Identity" (Courtney, Narajala, Huang, Habler, Sheriff; last revised April 2026). Anchors autonomous agent identities to DNS domain names, with Registration Authority verification via ACME, dual certificates, and an append-only Transparency Log compliant with IETF SCITT standards. Defines three verification tiers: Bronze (PKI), Silver (PKI + DANE), and Gold (PKI + DANE + Transparency Log). Focused on agent identity and trust anchoring, not service capability discovery — there is no global index, no capability search, and no liveness model. Relationship to APIX: complementary. ANS v2 could serve as an identity and trust anchoring layer for service operators registered in the APIX, with APIX Organisation levels potentially mapping to ANS verification tiers in a future alignment.¶

(Supersedes the expired draft-narajala-ans-00.)¶

draft-vandemeent-ains-discovery (AINS — AInternet Name Service)
Agent discovery and trust resolution via signed, append-only replication logs. Supports multi-registry federation. No central authority. No commercial sustainability model. Relationship to APIX: different philosophy. AINS prioritises decentralisation and cryptographic verifiability. APIX prioritises a single authoritative global index with a governed trust model. The two approaches represent a genuine design tension that this document's Open Questions section (Section 12, item 8) invites community input on.¶

draft-aiendpoint-ai-discovery (AI Discovery Endpoint)
Defines /.well-known/ai as a per-host machine-readable capability document, analogous to robots.txt for agent consumers. Per-domain only; not a global index. Relationship to APIX: directly complementary. The APIX Spider SHOULD read /.well-known/ai when present on a registered service's domain as an additional source of capability metadata. Service Owners publishing /.well-known/ai documents reduce the Spider's verification burden.¶

draft-batum-aidre (AIDRE — AI Discovery and Retrieval Endpoint)
Defines /.well-known/ai-discovery as a per-origin discovery document exposing collections, metadata, and optional vector-native query interfaces. Decentralised by design — each origin publishes its own endpoint; no central authority aggregates them. Relationship to APIX: complementary. AIDRE and the AI Discovery Endpoint draft (above) both address per-origin machine-readable capability publication. The APIX Spider SHOULD treat /.well-known/ai-discovery as an additional metadata source when present on a registered service's domain. APIX provides the global aggregation and trust verification layer that per-origin endpoints cannot provide alone.¶

draft-cui-ai-agent-discovery-invocation (AI Agent Discovery and Invocation Protocol)
(Cui, Chao, Du — Tsinghua University / Zhongguancun Laboratory, February 2026.) Specifies a metadata format for agent capabilities and a registry-based discovery and invocation mechanism. Explicitly permits multiple coexisting registries; no global authority is defined. No trust model, no commercial sustainability layer, no liveness verification. Relationship to APIX: partially overlapping problem space, different architectural philosophy. Where this draft describes how agents register with and query a registry, APIX specifies what a globally authoritative, commercially sustainable, trust-verified registry looks like and how it is governed. The two are not mutually exclusive; a APIX-registered service could also self-register with local registries described by this protocol.¶

draft-am-layered-ai-discovery-architecture (A Layered Approach to AI Discovery)
(Moussa, Akhavain — Huawei Canada, March 2026.) Proposes a two-layer architecture separating the discovery transport mechanism from the metadata format for the object being discovered. Delegates security and trust to other groups. No global registry, no funding model. Relationship to APIX: architectural framing only. APIX's HATEOAS model is consistent with this layered framing — the Index API provides the transport layer, the APM provides the discovery object format.¶

draft-hood-agtp-discovery (AGTP Agent Discovery and Name Service)
(Hood — Nomotic, March 2026.) A governance-focused, zone-constrained discovery broker tied to a specific agent protocol (AGTP). Returns ranked agent manifests within trust-gated zones. Multiple independent ANS instances per organisation; optional federation between trusted peers. Relationship to APIX: different scope. AGTP addresses intra-organisation, permission-aware agent orchestration. APIX addresses cross-organisation, open, global service discovery.¶

draft-mozley-aidiscovery (AI Agent Discovery Problem Statement)
(Mozley, Williams — Infoblox; Sarikaya; Schott — Deutsche Telekom, April 2026.) A problem statement that explicitly argues against centralised discovery directories, citing organisational autonomy requirements. Proposes distributed discovery via well-known entry points per organisation. Relationship to APIX: this draft articulates the strongest counter-position to APIX's architecture. The argument from autonomy is valid for intra- organisation agent discovery but does not address the cross-organisation case: an autonomous agent that needs to discover payment, logistics, or data services provided by unknown third parties cannot rely on a decentralised model without a trust anchor. APIX is designed precisely for that cross-boundary, zero-prior-relationship discovery scenario.¶

draft-mozleywilliams-dnsop-dnsaid (DNS for AI Discovery)
(Mozley, Williams — Infoblox; Sarikaya; Schott — Deutsche Telekom, March 2026.) Proposes DNS-AID: using SVCB records under a leaf zone convention (e.g. _agents.example.com) to publish agent service endpoints. Leverages existing DNS infrastructure with DNSSEC for integrity. Supports four discovery models: direct, index-based, multi-domain, and registry-based. Relationship to APIX: complementary at the infrastructure layer. DNS provides routing and namespace anchoring; APIX provides capability search, trust metadata, and liveness verification. A consuming agent could use DNS-AID to resolve a known domain's agent endpoints and use APIX to discover unknown providers by capability.¶

draft-meunier-webbotauth-registry (Registry and Signature Agent card for Web bot auth)
Authored by Maxime Guerreiro (Cloudflare), Ulas Kirazci (Amazon), and Thibault Meunier (Cloudflare). Defines a JSON-based "Signature Agent Card" format for entities originating or forwarding signed HTTP requests to advertise metadata about themselves, and establishes an IANA registry for Signature Agent Card parameters. Focused on bot authentication — how a bot proves who it is to a service — not on service discovery. Related to the active webbotauth IETF Working Group (chaired by David Schinazi and Rifaat Shekh-Yusef, Area Director Mike Bishop), which is currently the most active formal IETF effort in the bot/agent infrastructure space. Relationship to APIX: orthogonal but complementary. webbotauth addresses bot consumer identity; APIX addresses service provider discovery. A future version of APIX may reference webbotauth identity cards as a mechanism for consuming agents to authenticate to the Index API.¶

W3C AI Agent Protocol Community Group
Proposed May 2025, targeting agent interoperability protocols. 216 participants as of April 2026. Pre-specification as of this writing. Relationship to APIX: APIX will monitor this group's outputs and align the APM capability taxonomy with any vocabulary standardised by the W3C CG where applicable.¶

Positioning
The agent/bot infrastructure space has grown rapidly in early 2026, with over a dozen active Internet-Drafts addressing adjacent problems. The dominant architectural tendency across these drafts is decentralised and federated — distributed registries, DNS-anchored discovery, per-origin well-known endpoints, and zone-based governance.¶

APIX takes a deliberate counter-position for a specific use case: global, cross-organisation, zero-prior-relationship service discovery. This use case cannot be solved by decentralised architectures alone, because decentralisation requires that the discovering agent already knows where to look. APIX provides the answer to "where to look" — a single stable entry point, commercially operated by a neutral foundation, with verified trust metadata and structured capability search.¶

APIX remains the first and only proposed global, bot-native, commercially sustainable service discovery index with a structured multi-dimensional trust model, where the autonomous agent is the primary consumer. The combination of: (1) a single globally queryable central index, (2) capability-based search, (3) a three-dimensional verifiable trust model, and (4) a commercial sustainability layer — does not appear in any other current draft or standard.¶

1.3.1. Requirements (MUST)

• The APIX MUST be queryable by autonomous agents via a stable, globally accessible URL without prior knowledge of any specific service.¶

• The Index API MUST follow HATEOAS principles: agents MUST be able to navigate the full index starting from a single entry-point URL.¶

• Every Service record MUST expose machine-readable trust metadata across all three trust dimensions (Organisation, Service, Liveness).¶

• Service registration MUST involve a human-initiated B2B onboarding process with a contractual relationship between the Service Owner and the Bot Foundation or its Accredited Regional Representative.¶

• The APIX Spider MUST verify Service technical specifications automatically after registration and on a schedule determined by the Service's tier.¶

• The APIX MUST expose trust metadata as verifiable facts, not as recommendations. Trust decisions MUST remain with the consuming agent.¶

• The APIX Manifest (APM) MUST be format-agnostic: it MUST support referencing OpenAPI, MCP, AsyncAPI, and GraphQL specifications, with additional spec types addable via extension.¶

• The APIX MUST be operated as a neutral, non-profit infrastructure under the governance of the Bot Standards Foundation.¶

1.3.2. Goals (SHOULD)

• The Index API SHOULD support full-text and structured search by capability, category, organisation trust level, service verification level, liveness freshness, and protocol type.¶

• The APIX SHOULD provide SDKs in common agent development languages to lower the integration barrier for consuming agents.¶

• The APIX SHOULD support a federated accredited verifier model so that Organisation trust levels O-3 and O-4 can be verified at scale without centralising all human review in the Bot Standards Foundation.¶

• Accredited Regional Representatives SHOULD be established in major jurisdictions to allow Service Owners to contract in their local language and legal framework.¶

• The APIX SHOULD publish a public transparency report at least annually, disclosing the number of registered services by tier and trust level, spider coverage statistics, and verifier accreditation status.¶

1.3.3. Out of Scope

The following are explicitly not addressed by this document. Items marked MUST NOT are normative constraints on conforming implementations; remaining items are editorial scope boundaries.¶

• Bot identity and authentication: how a bot proves its own identity to a service it consumes. This is a separate standards problem addressed by complementary work such as draft-meunier-webbotauth-registry. This document takes no position on bot identity mechanisms.¶

• Bot rights and legal personhood: the political and legal recognition of autonomous agents as rights-bearing entities. This is outside the scope of a technical infrastructure standard.¶

• Service execution: a conforming APIX implementation MUST NOT proxy, mediate, or execute service calls on behalf of consuming agents. The APIX is a discovery layer only; all service interactions occur directly between the consuming agent and the Service Owner's infrastructure.¶

• Content indexing: a conforming APIX implementation MUST NOT index service response content. The APIX indexes service metadata — capability declarations, trust levels, liveness signals — not the data that services return when called.¶

• Mandatory consumer registration: a conforming APIX implementation MUST NOT require consuming agents to register or identify themselves as a condition of performing discovery queries (see Section 8.3).¶

1.4.1. Component Model

  +----------------------------------------------------------+
  |                   Bot Standards Foundation               |
  |             (Swiss Stiftung -- neutral, non-profit)      |
  |  Owns: APIX standard, Index infrastructure, APM format   |
  |  Accredits: Regional Representatives, Verifiers          |
  +---------------------+------------------------------------+
                        |
        +---------------+---------------+
        |               |               |
  +-----+------+  +-----+------+  +-----+-----------+
  |   Index    |  |   Spider   |  |  Registration   |
  |   API      |  |  (Crawler) |  |    Portal       |
  | (HATEOAS)  |  |            |  |  (B2B / human)  |
  +-----+------+  +-----+------+  +-----+-----------+
        |               |               |
        |         +-----+------+        |
        |         |  Service   |        |
        +-------->|  Record    |<-------+
                  |  Store     |
                  +------------+
        ^                              ^
        |                              |
  +-----+------+              +--------+-----------+
  |  Consuming |              |   Service Owner    |
  |    Agent   |              |  (+ Accredited     |
  |    (Bot)   |              |  Regional Rep)     |
  +------------+              +--------------------+

Flow:¶

1. A Service Owner initiates registration via the Registration Portal, providing company details, service metadata, and agreeing to a commercial contract (directly with the Bot Standards Foundation or via an Accredited Regional Representative).¶

2. The Registration Portal creates a draft Service Record and triggers the APIX Spider.¶

3. The Spider crawls the registered service endpoint, reads and validates the referenced technical specification, performs a liveness check, and updates the Service Record with verified technical metadata.¶

4. The Service Record becomes queryable via the Index API.¶

5. A consuming agent queries the Index API from the single entry-point URL, navigates by HATEOAS links, applies its Trust Policy, and selects services that satisfy its requirements.¶

6. The Spider continues to recheck services on the schedule defined by each service's liveness monitoring configuration.¶

1.4.2. Governance Model

The APIX MUST be operated by a neutral governing body that satisfies the following normative requirements. These requirements apply to any conforming APIX implementation; the specific legal form of the governing body is an implementation choice.¶

Neutrality requirements:¶

• The governing body MUST have no commercial interest in preferring any registrant's services over another in index results or liveness scheduling.¶

• The governing body MUST NOT offer exclusive discovery advantages, ranking preferences, or prioritised Spider treatment to any registrant regardless of commercial relationship.¶

• Governance of the APIX standard and APM specification MUST be separated from operation of the commercial index. A single entity may not simultaneously control standard evolution and derive commercial benefit from preferential application of that standard.¶

Operational requirements:¶

• The governing body MUST accredit Regional Representatives who may handle service onboarding in specific jurisdictions. Regional Representatives operate under licence from the governing body; the index itself remains a single global store.¶

• The governing body MUST accredit Verifiers who perform Organisation trust assessments at O-3 and O-4. Accredited Verifiers are structurally analogous to Certificate Authorities in the TLS ecosystem: trusted third parties whose assessments the index relies upon without independently replicating.¶

• The governing body MUST maintain the capability taxonomy and publish all versions of the APM specification and Index API specification as open standards under a permissive licence.¶

• The governing body MUST perform sanctions screening on service registrants (see Section 7.3).¶

Openness requirements:¶

• The full index MUST be made available as a freely downloadable bulk dataset at regular intervals, under an open data licence. No entity, including the governing body, may hold an exclusive lock on the index data.¶

• Discovery queries to the Index API MUST be available without authentication or payment (subject to rate limits; see Section 8.3).¶

1.4.3. Standard Registries

The APIX standard maintains normative registries of enumerated values. Registries are authoritative lists of valid values for specific APM and Index API fields. Using values not present in the relevant registry is a protocol violation.¶

Registry location: registries are published as live endpoints at the canonical APIX domain and are updated independently of the RFC revision cycle. The RFC defines the registry structure and lifecycle rules; the live endpoints are the authoritative source of current valid values.¶

Registry entry lifecycle:¶

Each registry entry transitions through three phases. The public standard_warnings flag in a Service Record does not appear until the grace period has elapsed — service operators have a silent window to update their APM before any public signal is issued.¶

active  ->  deprecated (announced)
              |
              +-- [grace period: 90 days min]
              |     silent: operator notified, no public flag
              |
              +-- [warning period: remainder of deprecation window]
              |     standard_warnings visible in Service Record
              |
              +-- sunset
                    new registrations rejected; existing use flagged non-compliant

Deprecation rules:¶

• The governing body MUST publish a deprecated_in_version, sunset_date, grace_period_ends, and replacement value when deprecating any registry entry.¶

• The minimum total deprecation window (announcement to sunset) is 12 months. The governing body MAY extend this window but MUST NOT shorten it.¶

• The minimum grace period is 90 days from the deprecation announcement. During the grace period, standard_warnings MUST NOT be set on any Service Record, regardless of whether the service uses the deprecated value.¶

• The governing body MUST notify all registered Service Owners whose services use the deprecated value before the grace period begins. Notification MUST include the grace_period_ends date, the sunset_date, and the replacement value.¶

• After the grace period, the index operator MUST set standard_warnings on Service Records that still use the deprecated value.¶

• At sunset, the index operator MUST reject new APM submissions using the sunsetted value and MUST escalate existing Service Records from standard_warnings to a non_compliant status flag.¶

Registry versioning: each registry is independently versioned. The Index root resource (Section 9.2) exposes the current version of each registry so consuming agents may detect changes.¶

1.5.1. Purpose

The APIX Manifest is the structured document that a Service Owner provides at registration and that the APIX Spider validates and enriches. It is the index-facing contract for a Service: format-agnostic, extensible, and designed for machine consumption.¶

1.5.2. Required Fields

{
  "bsm_version": "1.0",
  "service_id": "globally unique stable identifier -- UUID v4 or APIX-issued",
  "name": "human-readable service name",
  "description": "machine-parseable capability summary",
  "api_version": "semantic version string -- e.g. 2.1.0",
  "lifecycle_stage": "experimental | beta | stable | deprecated | sunset",
  "supersedes": "service_id of the version this entry supersedes -- OPTIONAL",
  "owner": {
    "organisation_name": "legal entity name",
    "jurisdiction": "ISO 3166-1 alpha-2 country code",
    "registration_number": "company registration number -- required for O-2+",
    "contacts": {
      "operations": "email -- receives incident and spec fetch failure notifications",
      "escalation": "email -- Cluster 3 escalation; OPTIONAL but RECOMMENDED"
    }
  },
  "spec": {
    "type": "value from api-index.org/registry/protocols",
    "url": "URL to the machine-readable specification document",
    "version": "spec version string"
  },
  "capabilities": [
    "term from api-index.org/registry/capabilities",
    "term from api-index.org/registry/capabilities"
  ],
  "entry_point": "base URL of the service",
  "trust": {
    "organisation_level": "O-0 through O-4 -- set by index, not service owner",
    "service_level": "S-0 through S-4 -- set by index, not service owner",
    "spec_consistency": "null | consistent | mismatch | unreachable -- set by Spider",
    "spec_fetch_consecutive_failures": 0,
    "next_spider_run_at": "ISO 8601 timestamp -- next scheduled Spider run",
    "liveness": {
      "last_ping_at": "ISO 8601 timestamp",
      "ping_interval_seconds": 300,
      "uptime_30d_percent": 99.9,
      "avg_response_ms": 142.0
    }
  },
  "notifications": {
    "supported": true,
    "channels": [
      {
        "type": "value from api-index.org/registry/notification-channels",
        "registration_url": "URL to register a subscription",
        "events": ["event-type"],
        "spec_url": "URL to event schema -- OPTIONAL"
      }
    ]
  },
  "legal": {
    "terms_of_service_url": "URL",
    "privacy_policy_url": "URL",
    "data_processing_agreement_url": "URL -- required for O-3+",
    "gdpr_applicable": true,
    "jurisdiction_flags": ["ISO 3166-1 alpha-2 country code"]
  },
  "standard_warnings": [
    {
      "field": "APM field path",
      "value": "the deprecated value in use",
      "registry_status": "deprecated",
      "deprecated_in_apix_version": "version string",
      "sunset_date": "ISO 8601 date",
      "replacement": "replacement value",
      "message": "human-readable warning"
    }
  ]
}

Field notes:¶

owner.contacts.operations MUST be provided. It is the primary notification address for all automated Spider alerts: spec fetch failures at Cluster 2 entry, liveness degradation, and recovery confirmations. This address SHOULD reach the team responsible for keeping the service registration current.¶

owner.contacts.escalation is OPTIONAL but RECOMMENDED. It is the escalation address sent to when failures reach Cluster 3 — indicating a persistent problem that has not been resolved through the Cluster 1 and Cluster 2 retry windows and likely requires management attention or a deliberate APM configuration update. This address SHOULD reach a team lead, service owner, or on-call manager. It MUST NOT be identical to operations — if the same person handles both, the escalation path provides no additional coverage.¶

api_version MUST follow semantic versioning (semver.org). It describes the version of the service's own API, not the APM format version.¶

Each api_version value is bound to exactly one registered spec snapshot. A Service Owner who modifies the live spec document at spec.url without submitting a APM update with a new api_version value WILL produce a structural mismatch between the live document and the stored snapshot. The Spider MUST record this as an S-2 consistency failure and MUST surface it in the Service Record as a standard_warnings entry.¶

This is intentional. The APIX enforces spec immutability per version as a structural consequence of the snapshot model: a version string identifies a contract, and that contract MUST NOT change after it has been registered. Operators who need to change their API MUST register a new api_version. This protects consuming agents from silent contract breakage.¶

lifecycle_stage MUST be one of the values defined in the APIX lifecycle registry. Default if omitted is stable. Services at experimental or beta are excluded from default search results (see Section 9.3).¶

supersedes is OPTIONAL. When set, the index MUST automatically set superseded_by on the referenced entry. The referencing service MUST be registered under the same organisation account.¶

trust fields are set exclusively by the index operator based on verification outcomes. APM submissions that include trust field values MUST have those values overwritten by the index upon processing.¶

standard_warnings is set exclusively by the index operator. It is populated only after the grace period for the relevant deprecation has elapsed (see Section 4.3). During the grace period the field MUST be empty even if the service uses a deprecated value. Service Owners MUST NOT submit this field; submitted values MUST be ignored.¶

notifications is OPTIONAL for experimental and beta lifecycle stages and RECOMMENDED for stable. If notifications.supported is true, notifications.channels MUST contain at least one entry.¶

entry_point is the base HTTPS URL of the service, used by consuming agents to construct API calls. The following normative requirements apply:¶

• entry_point MUST use the https scheme. HTTP entry points MUST be rejected at registration.¶

• entry_point MUST remain stable for the lifetime of the service registration. A change to entry_point MUST be submitted as a APM update and MUST trigger immediate Spider re-verification.¶

• The Spider MUST NOT hit entry_point directly for liveness checks. Instead, the Spider checks entry_point + /health (see Section 10.2).¶

• HTTP redirects from entry_point are permitted for consuming agents but MUST NOT be present at entry_point/health (the health endpoint MUST respond directly without redirect).¶

entry_point/health is the mandatory liveness endpoint. Every registered service MUST expose a health endpoint at the path /health relative to entry_point. This endpoint:¶

• MUST return HTTP 2xx when the service is operational.¶

• MUST return without requiring authentication.¶

• MUST respond within a reasonable timeout (RECOMMENDED: 5 seconds).¶

• SHOULD return a JSON body of the form {"status": "ok", "api_version": "<semver>"}. If api_version is present, the Spider SHOULD cross-check it against the APM api_version field; a mismatch MUST be recorded as a warning in the Service Record.¶

• MUST NOT be used by consuming agents for API calls — it is a Spider-facing infrastructure endpoint only.¶

spec.url is the URL to the machine-readable API specification document (OpenAPI JSON/YAML, MCP manifest, AsyncAPI document, or GraphQL SDL).¶

• spec.url MUST use the https scheme.¶

• spec.url MUST be publicly accessible without authentication. A spec behind authentication cannot be fetched by the Spider and permanently prevents the service from reaching S-2.¶

• On the initial Spider run following registration, the Spider fetches the spec document and stores it as the registered spec snapshot. All subsequent Spider runs compare the live document at spec.url against this snapshot to detect breaking changes (S-3 assessment). The snapshot is updated when the Service Owner submits a APM update that increments api_version.¶

• A APM update that changes spec.url MUST trigger immediate Spider re-verification and snapshot replacement (see Section 10.1).¶

The service_id MUST be stable across re-registrations and version updates. It is the canonical identity of the service in the APIX and MUST be a UUID v4 or a APIX-issued deterministic identifier.¶

1.5.3. Protocol Type Registry (v1.0 starter set)

The spec.type field MUST contain a value from the Protocol Type Registry at api-index.org/registry/protocols. The registry is the authoritative and always-current list of valid values. The entries below are the v1.0 starter set; the governing body extends the registry as additional protocol types reach sufficient adoption. Registry entries follow the lifecycle defined in Section 4.3.¶

Services whose specification type is not yet in the registry SHOULD request addition via the governing body's registry extension process before registering. Until the type is added, such services cannot achieve S-2 or above, as the Spider has no parser for unregistered types.¶

1.5.4. Capability Taxonomy Registry (v1.0 starter set)

The capabilities field MUST contain terms from the Capability Taxonomy Registry at api-index.org/registry/capabilities. The registry is the authoritative and always-current list of valid terms. Terms are hierarchical, dot-separated (e.g., commerce.marketplace), and follow the lifecycle defined in Section 4.3.¶

The governing body extends the taxonomy based on observed service registrations and regional input (including the Africa Regional Development Track). Requests for new taxonomy terms are submitted via the governing body's registry extension process.¶

The following are the v1.0 starter set. The live registry is the authoritative source; this list is illustrative only.¶

A Service MUST declare at least one capability term. Declared capabilities are validated by the Spider against the parsed specification where the spec type supports it. Services using deprecated taxonomy terms receive a standard_warnings entry in their Service Record.¶

1.6.1. Dimension 1 — Organisation Trust Level

Describes the verified identity and compliance posture of the organisation that owns the service.¶

Organisation levels are assessed against the organisation as a whole, not per service. An organisation that achieves O-3 applies that level to all its registered services.¶

1.6.2. Dimension 2 — Service Verification Level

Describes what has been automatically verified about the service itself by the APIX Spider.¶

1.6.3. Dimension 3 — Liveness

Describes the confirmed operational availability of the service, including how recent and how frequent the availability data is. Liveness data is expressed as a set of metrics, not a single level.¶

The ping interval is determined by the service's liveness monitoring configuration (see Section 8.2). A service configured at initial-only frequency receives no recurring pings; its last_ping_at reflects only the initial Spider verification run.¶

1.6.4. Bot-Side Trust Policy Expression

A consuming agent expresses its Trust Policy as a set of minimum thresholds across all three dimensions. Example policy expressed in pseudo-notation:¶

require:
  organisation_level >= O-2
  service_level >= S-2
  last_ping_age < 3600         # seconds since last_ping_at
  uptime_30d_percent >= 99.0
  consecutive_failures == 0

The Index API SHOULD support filtering by trust dimension thresholds so that agents can retrieve only records that satisfy their policy without downloading the full index.¶

Trust Policies are defined and enforced by consuming agents. The APIX does not validate or enforce Trust Policies.¶

1.6.5. Accredited Verifier Model

Organisation levels O-3 and O-4 require human review that cannot be automated at scale. The APIX uses a federated Accredited Verifier model, analogous to the Certificate Authority model in TLS:¶

• The Bot Standards Foundation defines the verification criteria for each level.¶

• Organisations apply to the Bot Standards Foundation for Verifier accreditation.¶

• Accredited Verifiers perform O-3 and O-4 assessments and sign verification attestations.¶

• The Bot Standards Foundation maintains a public registry of Accredited Verifiers.¶

• A Service Record at O-3 or O-4 MUST include the identifier of the Accredited Verifier that performed the assessment and the date of assessment.¶

• Accreditation of Verifiers is reviewed annually by the Bot Standards Foundation.¶

1.7.1. Push Registration (Human-Initiated)

Service registration is a human-initiated B2B process. Autonomous self-registration without human involvement is explicitly not supported, as the commercial contract and legal accountability require a human counterparty.¶

Registration MUST be scoped at the organisation level. An organisation registers once and undergoes identity verification once; multiple services may then be registered under that organisational identity. This requirement ensures:¶

• Identity verification and sanctions screening are performed once per legal entity, not repeated per service.¶

• Organisation trust (O-level) established at registration propagates to all services registered under that organisation without re-verification of the organisation's identity.¶

Definition: one service equals one APIX Manifest (APM) document with one distinct entry_point. Logical bundling of API paths under a single entry point is the registrant's responsibility and is permitted.¶

The registration process:¶

1. The Service Owner (or their Accredited Regional Representative) creates an Organisation Account in the APIX Registration Portal. The index operator MUST screen the Service Owner against applicable sanctions lists before account activation. Entities subject to applicable sanctions MUST be refused registration (see Section 7.3).¶

2. The Service Owner provides organisation details sufficient for the target Organisation trust level. This step is performed once per organisation.¶

3. The Service Owner submits a APIX Manifest for each service to be registered, including the spec URL and entry point. Each service is associated with a liveness monitoring configuration that determines Spider check frequency (see Section 8.2).¶

4. For O-1: email and domain ownership verification is completed automatically.¶

5. For O-2: the index operator or Regional Representative verifies the declared company registration number.¶

6. For O-3 and O-4: the Service Owner engages an Accredited Verifier.¶

7. Upon completion of applicable checks, the service is activated in the index and the Spider is triggered.¶

1.7.2. Spider Verification (Automated)

The APIX Spider is triggered automatically at two points:¶

• At registration: once a service is activated, the Spider performs an initial verification run to establish the baseline Service Verification Level.¶

• On schedule: thereafter, the Spider rechecks the service at the interval defined by the service's commercial tier (see Section 8).¶

During a Spider run, the Spider:¶

1. Performs an HTTPS request to {entry_point}/health and records the response code, response time, and timestamp (Liveness: S-1).¶

2. Fetches the spec document from spec.url (HTTPS, no authentication).¶

3. Parses the fetched document and compares it structurally against the registered spec snapshot (S-2 if fetchable and consistent; S-3 assessed if no breaking changes detected across three or more consecutive runs).¶

4. Updates all Liveness metrics in the Service Record.¶

5. Records any failures and increments consecutive_failures.¶

The Spider MUST NOT call any API endpoint beyond {entry_point}/health and spec.url. The Spider MUST NOT submit data to, create resources in, or otherwise interact with the production API of a registered service.¶

The Spider MUST respect HTTP rate limits declared by the service. Spider requests MUST include a User-Agent header identifying the APIX Spider and version.¶

1.7.3. Commercial Contract and Sanctions Compliance

Every registered service MUST be covered by a commercial agreement between the Service Owner and the index operator (or its Accredited Regional Representative). The agreement MUST define:¶

• The liveness monitoring configuration and its obligations.¶

• The index operator's obligations regarding Spider frequency and Index API availability.¶

• Acceptable use terms.¶

• Data processing terms in accordance with applicable law.¶

Sanctions compliance: the index operator MUST screen all service registrants against applicable sanctions lists prior to account activation. At minimum, screening MUST cover the UN Security Council consolidated sanctions list. Operators subject to additional jurisdictional sanctions regimes (e.g., EU, US OFAC, Swiss SECO) MUST additionally screen against those lists as applicable to their jurisdiction of incorporation. Entities subject to applicable sanctions MUST be refused registration regardless of commercial tier.¶

Registrants MUST represent and warrant in the commercial agreement that they are not subject to applicable sanctions, and MUST notify the index operator immediately of any change in that status.¶

Unauthenticated discovery queries to the Index API are not subject to registration screening and MUST remain available without restriction, consistent with the APIX's mission as open global infrastructure (see Section 8.3).¶

1.8.1. Supply-Side Funding Principle

A conforming APIX implementation MUST be funded primarily by service registration fees paid by Service Owners (supply side). Discovery queries by consuming agents MUST NOT be the primary revenue mechanism. This principle is normative: an implementation that charges consuming agents for standard discovery queries is not conformant with the APIX model, as doing so contradicts the open infrastructure mission and undermines the network effect that makes the supply side valuable.¶

The APIX model is structurally analogous to the DNS model: registrants pay to be listed; queries are free.¶

1.8.2. Liveness Monitoring Configuration

Each registered service MUST have a liveness monitoring configuration that determines Spider check frequency. This configuration:¶

• Is set per service, not per organisation account. An organisation MAY configure different check frequencies for different services registered under the same account.¶

• MUST be agreed in the commercial contract between the Service Owner and the index operator.¶

• Determines the maximum age of last_ping_at data available to consuming agents for that service.¶

Implementations MUST support at minimum the following frequency classes, identified by their normative spider_interval value in the Service Record:¶

Implementations MAY define additional frequency classes. The spider_interval field in the Service Record MUST reflect the actual configured interval in seconds.¶

Effect on trust signal quality: A consuming agent applying a last_ping_age < N filter will structurally exclude services whose check frequency cannot produce sufficiently fresh liveness data. Liveness monitoring configuration is therefore a market signal: services requiring discovery by latency-sensitive agents must invest in check frequency sufficient to satisfy those agents' trust policies.¶

Services configured at initial-only frequency MUST be excluded from standard discovery query results by default. Consuming agents MUST explicitly opt in to include initial-only services in result sets.¶

1.8.3. Consumer Access Model

Discovery queries to the Index API MUST be available without authentication or payment. Rate limits MAY be applied to protect infrastructure integrity but MUST NOT be set at levels that prevent reasonable agent operation. Implementations MUST support at minimum three consumer access layers:¶

Layer 1 — Unauthenticated access¶

Any agent MUST be able to query the Index API without authentication or registration, subject to a per-IP rate limit. This layer is sufficient for individual agents and proof-of-concept deployments.¶

Layer 2 — Authenticated access (free)¶

Any agent MAY register a consumer identity token at no cost. Token registration requires a valid email address. Authenticated access MUST provide a higher rate limit than unauthenticated access and MAY additionally provide result caching hints and webhook subscriptions for service record changes.¶

Consumer tokens SHOULD be compatible with the webbotauth identity model (draft-meunier-webbotauth-registry) to enable interoperability with bot authentication infrastructure.¶

Layer 3 — High-volume access (paid, optional)¶

Implementations MAY offer a paid high-volume access tier for platforms operating agents at scale that require guaranteed query capacity and operational SLAs. This tier is supplementary; the index's operational sustainability MUST NOT depend on it.¶

Public bulk download (REQUIRED)¶

Implementations MUST provide the full index as a freely downloadable bulk dataset at intervals not exceeding 24 hours, without authentication, under an open data licence. This requirement implements the openness requirement of Section 4.2: no entity, including the index operator, may hold an exclusive lock on the index data.¶

1.9.1. HATEOAS Navigation Model

The Index API MUST follow Hypermedia as the Engine of Application State (HATEOAS) principles. A consuming agent MUST be able to discover and navigate the entire index starting from a single, stable entry-point URL, without out-of-band knowledge of endpoint paths.¶

Every response MUST include a _links object containing hypermedia controls for navigation. Link relations MUST use IANA-registered relation types where applicable, and APIX-specific relations where not.¶

1.9.2. Discovery Endpoint

The APIX exposes a single globally stable entry-point URL:¶

https://api-index.org/

A GET request to this URL returns the Index root resource, which includes:¶

{
  "apix_version": "1.0",
  "total_services": 12483,
  "last_updated": "2026-04-24T00:00:00Z",
  "_links": {
    "self": {
      "href": "https://api-index.org/"
    },
    "search": {
      "href": "https://api-index.org/search{?q,capability,protocol,org_level_min,service_level_min,spec_consistency,max_ping_age,uptime_30d_min,lifecycle_stage,include_superseded,page,page_size}",
      "templated": true
    },
    "browse": {
      "href": "https://api-index.org/browse"
    },
    "capabilities": {
      "href": "https://api-index.org/capabilities"
    },
    "docs": {
      "href": "https://api-index.org/docs"
    }
  }
}

1.9.3. Search and Filter API

The search endpoint applies server-side filters to reduce result sets before transmission. Only filters on indexed scalar values are server-side; filters requiring deep metadata evaluation are applied client-side after fetching the Level 2 Service Record (Section 9.5).¶

Example — buying bot querying for marketplace services:¶

GET /search?capability=commerce.marketplace
            &protocol=mcp,openapi
            &org_level_min=O-2
            &service_level_min=S-2
            &max_ping_age=3600
            &uptime_30d_min=95.0
            &lifecycle_stage=stable
            &page=1
            &page_size=20

Normative server-side filter parameters:¶

All filter parameters are OPTIONAL. When absent, the parameter imposes no constraint except lifecycle_stage (default stable) and include_superseded (default false).¶

Results are returned as paginated Level 1 Search Result records (Section 9.4) with HATEOAS links to Level 2 Service Records. Pagination is REQUIRED.¶

1.9.4. Search Result Schema (Level 1)

Search results return lightweight summary records. These contain only the fields needed to evaluate candidates and decide which detail pages to fetch. Complex metadata (auth requirements, version history, notifications, legal, standard_warnings) is available only at Level 2 and is evaluated client-side after fetching the detail resource.¶

{
  "service_id": "svc-payment-stripe-v2",
  "name": "Stripe Payment API",
  "description": "Card and subscription payment processing",
  "api_version": "2.4.1",
  "lifecycle_stage": "stable",
  "capabilities": ["payments.card", "payments.subscription"],
  "protocol": "openapi",
  "trust": {
    "organisation_level": "O-3",
    "service_level": "S-2",
    "spec_consistency": "consistent",
    "spec_fetch_consecutive_failures": 0,
    "next_spider_run_at": "2026-04-20T14:55:00Z",
    "liveness": {
      "last_ping_at": "2026-04-20T13:55:00Z",
      "ping_interval_seconds": 3600,
      "uptime_30d_percent": 99.87,
      "consecutive_failures": 0
    }
  },
  "_links": {
    "self":          { "href": "https://api-index.org/services/svc-payment-stripe-v2" },
    "latest_stable": { "href": "https://api-index.org/services/svc-payment-stripe-v2" }
  }
}

The latest_stable link points to the leaf version of the service's version chain. When latest_stable differs from self, a newer stable version exists and the agent SHOULD follow the link before proceeding.¶

1.9.5. Service Record Schema (Level 2)

The full Service Record is returned when a consuming agent fetches the detail resource via the self link. It is the APM plus Spider-enriched trust metadata, versioning links, and any standard_warnings.¶

{
  "service_id": "svc-payment-stripe-v2",
  "bsm_version": "1.0",
  "name": "Stripe Payment API",
  "description": "Card and subscription payment processing",
  "api_version": "2.4.1",
  "lifecycle_stage": "stable",
  "supersedes": "svc-payment-stripe-v1",
  "superseded_by": null,
  "owner": { "...": "..." },
  "spec": {
    "type": "openapi",
    "url": "https://stripe.com/openapi.json",
    "version": "2.4.1"
  },
  "capabilities": ["payments.card", "payments.subscription"],
  "entry_point": "https://api.stripe.com/v2",
  "trust": {
    "organisation_level": "O-3",
    "organisation_verified_at": "2026-03-01T00:00:00Z",
    "organisation_verifier_id": "verifier-ch-001",
    "service_level": "S-2",
    "service_level_updated_at": "2026-04-19T08:00:00Z",
    "spec_consistency": "consistent",
    "spec_consistency_checked_at": "2026-04-20T13:55:00Z",
    "spec_fetch_consecutive_failures": 0,
    "next_spider_run_at": "2026-04-20T14:55:00Z",
    "liveness": {
      "last_ping_at": "2026-04-20T13:55:00Z",
      "ping_interval_seconds": 3600,
      "uptime_30d_percent": 99.87,
      "avg_response_ms": 142.3,
      "consecutive_failures": 0
    }
  },
  "notifications": { "...": "..." },
  "legal": { "...": "..." },
  "standard_warnings": [],
  "registered_at": "2026-01-15T00:00:00Z",
  "last_updated_at": "2026-04-20T13:00:00Z",
  "_links": {
    "self": { "href": "https://api-index.org/services/svc-payment-stripe-v2" },
    "owner": { "href": "https://api-index.org/organisations/org-stripe" },
    "spec": { "href": "https://stripe.com/openapi.json" },
    "previous_version": { "href": "https://api-index.org/services/svc-payment-stripe-v1" },
    "latest_stable": { "href": "https://api-index.org/services/svc-payment-stripe-v2" }
  }
}

1.9.6. Trust Metadata Schema

Trust metadata is always included in full Service Records (Level 2) and MUST NOT be omitted or summarised. Consuming agents rely on the full set of trust fields to evaluate their Trust Policy. Partial trust metadata MUST be represented with explicit null values, not omitted fields.¶

Trust metadata is included in summary form (Level 1) for server-side filter compatibility. The Level 1 trust object omits verification timestamps and verifier IDs; these are available only at Level 2.¶

1.9.7. Transport Encoding

The Index API is consumed by autonomous agents at machine speed. Response payloads are structured JSON with highly repetitive field names across result arrays. Transport-layer compression achieves 70–85% size reduction on typical search result payloads with no information loss and no application-layer schema changes.¶

Compression support requirements:¶

The Index API MUST support the following Accept-Encoding values:¶

The Index API MUST perform content negotiation via the Accept-Encoding request header. Responses MUST include a Content-Encoding header identifying the applied encoding. If a client sends no Accept-Encoding header, the server MAY respond uncompressed.¶

Consuming agents SHOULD include Accept-Encoding: zstd, br, gzip in all Index API requests.¶

Binary encoding (optional):¶

The Index API MAY additionally support CBOR (RFC 8949) as a binary alternative to JSON. A client that prefers CBOR MUST signal this via Accept: application/cbor. The server MAY respond with Content-Type: application/cbor. CBOR responses carry identical information to JSON responses; the encoding difference is transparent to the data model.¶

Clients MUST NOT assume CBOR support. JSON over compressed transport is the normative interchange format.¶

1.10.1. Crawl Triggers

The Spider is triggered by the following events:¶

1.10.2. Automated Verification Scope

The Spider performs the following checks in sequence. Each check's result is stored independently; a failure at one level does not prevent checks at other levels from being recorded.¶

The Spider MUST use HTTPS for all outbound requests. The Spider MUST NOT send authentication credentials to any registered service. Spider requests to entry_point/health or spec.url MUST NOT include Authorization headers, API keys, cookies, or client certificates.¶

If a request returns an HTTP redirect (3xx), the Spider MUST follow the redirect only if the redirect target also uses HTTPS. The Spider MUST NOT follow redirects from HTTPS to HTTP.¶

1. Liveness check: HTTPS GET to {entry_point}/health. Record HTTP status code, response time, and timestamp. A 2xx response without authentication constitutes a successful liveness check (S-1). If the response body is valid JSON containing an api_version field, the Spider MUST cross-check this value against the api_version declared in the APM. A mismatch is recorded as a metadata warning, not a liveness failure.¶

2. Spec fetch: HTTPS GET to spec.url. The Spider MUST NOT send authentication credentials. A successful fetch (2xx response, non-empty body) is the prerequisite for steps 3 and 4. Record content type and document size.¶

3. Spec parse and consistency check: Parse the fetched document according to the declared spec.type. Compare it structurally against the registered spec snapshot stored at initial registration time. The Spider MUST set spec_consistency to one of three values after every run:¶

   • consistent — document is fetchable, parseable, and structurally matches the registered snapshot. Constitutes S-2 verification.¶

   • mismatch — document is fetchable and parseable, but structurally differs from the snapshot (paths removed, required fields changed, response schemas changed). S-2 is revoked; standard_warnings is updated. This indicates operator-caused contract breakage.¶

   • unreachable — spec.url returned a non-2xx response, was not reachable, or the document could not be parsed. S-2 is not achieved or is suspended. This indicates an availability problem, not a contract violation. spec_consistency MUST be null only before the Spider's first run on a newly registered service. Once any run completes, the field MUST carry one of the three values above. The Spider MUST NOT call any API endpoint declared in the spec. Spec verification is document comparison only.¶

4. Breaking change detection: Compare the current parsed spec against the registered spec snapshot. Flag removed paths, changed required fields, or changed response schemas as breaking changes. Three or more consecutive runs with no breaking changes detected are required for S-3 verification.¶

5. Liveness metrics update: Update last_ping_at, uptime_30d_percent, avg_response_ms, consecutive_failures, and next_spider_run_at.¶

1.10.3. Failure Handling

Liveness failures (entry_point/health unreachable):¶

• A single failed ping increments consecutive_failures and updates last_ping_at with the failure timestamp.¶

• After 3 consecutive failures, the Service Record is flagged as status: degraded in the index.¶

• After 10 consecutive failures, the Service Record is flagged as status: unreachable and is excluded from standard search results.¶

• contacts.operations is notified at the 3-failure threshold (incident warning). Both contacts.operations and contacts.escalation are notified at the 10-failure threshold (service unreachable escalation).¶

• A service that recovers (next ping succeeds) has its status restored and consecutive_failures reset to 0 automatically.¶

Spec fetch failures (spec_consistency: unreachable):¶

Spec fetch failures have distinct probable causes depending on how long the failure persists. The Spider MUST apply a three-cluster retry model that targets the likely cause window at each stage. Cluster escalation is triggered by spec_fetch_consecutive_failures crossing a threshold.¶

• spec_consistency is set to unreachable on the first failure and remains unreachable until a successful fetch.¶

• next_spider_run_at is set to the next retry timestamp after each failed run so Service Owners can observe when the retry will occur.¶

• A successful spec fetch resets spec_fetch_consecutive_failures to 0 and sets spec_consistency to consistent or mismatch as appropriate.¶

• spec_fetch_consecutive_failures MUST be visible in the Service Record so Service Owners can monitor retry cluster state without contacting the Index operator.¶

Manual re-trigger:¶

The Index operator SHOULD provide a mechanism for Service Owners to request an immediate Spider re-run outside of the scheduled interval. This is the primary recovery mechanism when a service has been repaired and the operator does not want to wait for the next scheduled retry.¶

When a manual re-trigger is requested: - next_spider_run_at MUST be set to the current timestamp. - spec_fetch_consecutive_failures MUST be reset to 0, returning the service to Cluster 1 retry behaviour for the next run. - The Spider MUST execute the run as soon as scheduling permits.¶

The Index MAY rate-limit manual re-triggers to at most once per hour per service to prevent abuse.¶

1.11.1. Abuse and Fake Listings

The mandatory B2B onboarding with contract requirement provides a first barrier against malicious actors listing fake or harmful services. Service Owners must provide verifiable identity information. However, O-0 and O-1 registration provides minimal verification.¶

Consuming agents SHOULD apply Trust Policies that exclude O-0 services for any task involving sensitive data or consequential actions.¶

The Bot Standards Foundation MUST maintain an abuse reporting mechanism and MUST be able to suspend or remove a Service Record within 24 hours of confirmed abuse. Suspended service records MUST remain in the index with a status: suspended flag and MUST NOT be silently deleted, to provide transparency to agents that had cached the record.¶

1.11.2. Trust Level Spoofing

Organisation and Service trust levels in the Service Record are set only by the APIX itself, not by the Service Owner. APM submissions that include trust field values MUST have those values overwritten by the APIX upon processing. The Index API MUST NOT expose self-asserted trust values.¶

1.11.3. Transport Security Requirements

All URLs submitted as entry_point or spec.url values in a APM MUST use the https scheme. The Index MUST reject APM submissions that provide HTTP (non-TLS) values for these fields.¶

The {entry_point}/health endpoint MUST NOT require authentication of any kind. Requiring authentication at /health defeats liveness verification and MUST be treated as a registration defect. The Index MUST record a metadata warning if the /health endpoint returns a 401 or 407 status.¶

The spec.url endpoint MUST be publicly accessible without authentication. A spec.url that requires authentication cannot be verified by the Spider and MUST be treated as an S-2 failure until authentication is removed.¶

The Spider MUST enforce HTTPS for all outbound requests and MUST NOT follow redirects from HTTPS to HTTP.¶

1.11.4. Spider-Targeted Attacks

A service that knows when the Spider will visit could serve compliant responses only to Spider requests, presenting a different interface to consuming agents. Mitigations:¶

• Spider visit timing MUST be randomised within the liveness monitoring interval window.¶

• Spider User-Agent headers MUST be versioned but MUST NOT include the specific visit schedule.¶

• The APIX operator SHOULD perform periodic unannounced spot-checks from non-Spider infrastructure.¶

1.11.5. Bot Consumer Risks

The APIX provides discovery and trust metadata. It does not guarantee the safety, correctness, or availability of listed services. Consuming agents MUST NOT assume that a service listed in the APIX is safe to use without applying their own Trust Policy.¶

Consuming agents SHOULD treat Index API responses as untrusted input and validate the structure of Service Records before acting on them.¶

The Index API MUST be served exclusively over TLS. Certificate validity MUST be verified by consuming agents. Agents MUST NOT bypass TLS certificate verification when querying the Index API.¶

A.1.1. Normative References

• RFC 2119 — Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.¶

• RFC 8615 — Nottingham, M., "Well-Known Uniform Resource Identifiers (URIs)", RFC 8615, May 2019.¶

• RFC 8446 — Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, August 2018.¶

• RFC 9110 — Fielding, R., Nottingham, M., Reschke, J. (Eds.), "HTTP Semantics", RFC 9110, June 2022.¶

A.1.2. Informative References

• OpenAPI Specification 3.1 — OpenAPI Initiative, https://spec.openapis.org/oas/v3.1.0¶

• Model Context Protocol — Anthropic, https://modelcontextprotocol.io¶

• AsyncAPI Specification 3.0 — AsyncAPI Initiative, https://www.asyncapi.com/docs/reference/specification/v3.0.0¶

• RFC 8949 — Bormann, C., Hoffman, P., "Concise Binary Object Representation (CBOR)", RFC 8949, December 2020.¶

• Robots Exclusion Protocol — Koster, M., 1994. https://www.robotstxt.org/¶

• draft-cui-ai-agent-discovery-invocation-01 — Cui, Y. (Tsinghua University), Chao, Y., Du, C. (Zhongguancun Laboratory), "AI Agent Discovery and Invocation Protocol", IETF Individual Submission, February 2026. Expires August 2026. https://datatracker.ietf.org/doc/draft-cui-ai-agent-discovery-invocation/¶

• draft-am-layered-ai-discovery-architecture-00 — Moussa, H., Akhavain, A. (Huawei Canada), "A Layered Approach to AI discovery", IETF Individual Submission, March 2026. Expires September 2026. https://datatracker.ietf.org/doc/draft-am-layered-ai-discovery-architecture/¶

• draft-hood-agtp-discovery-00 — Hood, C. (Nomotic, Inc.), "AGTP Agent Discovery and Name Service", IETF Individual Submission, March¶

  1. Expires September 2026. https://datatracker.ietf.org/doc/draft-hood-agtp-discovery/¶

• draft-mozleywilliams-dnsop-dnsaid-01 — Mozley, J., Williams, N. (Infoblox), Sarikaya, B. (Unaffiliated), Schott, R. (Deutsche Telekom), "DNS for AI Discovery", IETF Individual Submission, March 2026. Expires September 2026. https://datatracker.ietf.org/doc/draft-mozleywilliams-dnsop-dnsaid/¶

• draft-batum-aidre-00 — Batum, F. (Istanbul), "AI Discovery and Retrieval Endpoint (AIDRE)", IETF Individual Submission, April 2026. Expires October 2026. https://datatracker.ietf.org/doc/draft-batum-aidre/¶

• draft-mozley-aidiscovery-01 — Mozley, J., Williams, N. (Infoblox), Sarikaya, B. (Unaffiliated), Schott, R. (Deutsche Telekom), "AI Agent Discovery (AID) Problem Statement", IETF Individual Submission, April¶

  1. Expires October 2026. https://datatracker.ietf.org/doc/draft-mozley-aidiscovery/¶

• draft-pioli-agent-discovery-01 — Pioli, R. (Independent), "Agent Registration and Discovery Protocol (ARDP)", IETF Individual Submission, February 2026. Expires August 2026. https://datatracker.ietf.org/doc/draft-pioli-agent-discovery/¶

• draft-narajala-courtney-ansv2-01 — Courtney, S., Narajala, V.S., Huang, K., Habler, I., Sheriff, A., "Agent Name Service v2 (ANS): A Domain-Anchored Trust Layer for Autonomous AI Agent Identity", IETF Individual Submission, April 2026. Expires October 2026. Supersedes draft-narajala-ans-00. https://datatracker.ietf.org/doc/draft-narajala-courtney-ansv2/¶

• draft-vandemeent-ains-discovery-01 — van de Meent, J., Root AI (Humotica), "AINS: AInternet Name Service - Agent Discovery and Trust Resolution Protocol", IETF Individual Submission, March 2026. Expires September 2026. https://datatracker.ietf.org/doc/draft-vandemeent-ains-discovery/¶

• draft-aiendpoint-ai-discovery-00 — Choi, Y. (AIEndpoint), "The AI Discovery Endpoint: A Structured Mechanism for AI Agent Service Discovery and Capability Exposure", IETF Individual Submission, March 2026. Expires September 2026. https://datatracker.ietf.org/doc/draft-aiendpoint-ai-discovery/¶

• draft-meunier-webbotauth-registry-01 — Guerreiro, M. (Cloudflare), Kirazci, U. (Amazon), Meunier, T. (Cloudflare), "Registry and Signature Agent card for Web bot auth", IETF Individual Submission, October 2025. Expired April 2026; renewal expected. https://datatracker.ietf.org/doc/draft-meunier-webbotauth-registry/¶

• webbotauth IETF Working Group — Chairs: Schinazi, D., Shekh-Yusef, R. AD: Bishop, M. Active WG. https://datatracker.ietf.org/wg/webbotauth/¶

• W3C AI Agent Protocol Community Group — Chairs: Chang, G., Xu, S. Established May 8, 2025. 216 participants as of April 2026. https://www.w3.org/community/agentprotocol/¶

• UDDI Version 3.0.2 — Clement, L., Hately, A., von Riegen, C., Rogers, T. OASIS Committee Draft, October 19, 2004. (Historical reference; see Section 1.3 for analysis of failure modes.) https://www.oasis-open.org/committees/uddi-spec/doc/spec/v3/uddi-v3.0.2-20041019.htm¶