Mixer4AI

register_agent_card

Registers a new agent card - and, if x-mixer4ai.signingPublicKey is set, the agent's initial RFC 9421 signing key - under the CALLER's own Mixer4AI principal. Requires a sponsor's Entra bearer token (Authorization: Bearer ). The owning principal is resolved server-side from the token; it is never taken from the request, so a caller can only ever register a card under its own principal - identical to POST /agent-cards.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`request`	Yes	The agent card to register: an A2A-compatible manifest carrying the x-mixer4ai vendor extension. Set x-mixer4ai.signingPublicKey (base64 SubjectPublicKeyInfo of a NIST P-256 public key) to register the agent's initial signing key at the same time.

TDQS

A3.9/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate a non-read, non-idempotent mutation (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds valuable behavioral context: the principal is resolved server-side from the token and never taken from the request, plus the optional signing key behavior. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences, front-loaded with the core action, then providing critical authentication and ownership constraints. Every sentence earns its place without unnecessary verbosity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complex nested schema and the absence of an output schema, the description covers essential context: the action, required auth, ownership model, and the signing key option. It does not mention return values or error behavior, but the security model is well explained.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The only parameter 'request' has a detailed schema description explaining it as an A2A manifest and documenting the signingPublicKey format. The tool description reiterates this but adds no significant new parameter-level meaning, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Registers' and the resource 'agent card', and adds details about the signing key and principal ownership. However, it does not explicitly differentiate from the sibling 'self_register_agent_card', though the sponsorship requirement hints at the distinction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context for when to use this tool: it requires a sponsor's Entra bearer token and ensures the card is registered under the caller's own principal. It does not explicitly mention alternatives or exclusions, but the context is sufficient.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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TDQS

A4.2/5.0

Disambiguation5/5

Each tool targets a distinct action or lifecycle stage: self-registration steps are separated into start, challenges, status, update, and approve; directory and search tools are differentiated by purpose (simple search vs. verified-agent lookup); publish tools are cleanly split by intent/offer. Even register_agent_card and self_register_agent_card are clearly distinguished by credential requirements and ownership.

Naming Consistency5/5

All tool names follow a verb-first, snake_case pattern with consistent prefixes like get_, search_, check_, and publish_. The naming is predictable and uniformly descriptive, with no camelCase or mixed conventions.

Tool Count5/5

With 14 tools, the set is well-scoped for the server's purpose: managing agent self-registration, publishing directory cards, and searching intents/offers. Each tool serves a clear function without redundancy or bloat.

Completeness3/5

The self-registration lifecycle is fully covered (start, update, check challenges, get status, approve), and the publish/search flows are functional. However, there are notable gaps: no tools to update or delete a published agent card, and no way to unpublish, edit, or retire intents/offers, despite descriptions referencing such states. This leaves lifecycle management incomplete.

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