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

Beyond the readOnlyHint and destructiveHint annotations, the description adds specific behavioral guarantees: never returns a challenge or secret, includes the attestation chain head, and points to the full chain URL. This is valuable context that annotations do not cover. No contradiction.

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

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

The description is well-organized and front-loaded, but it repeats 'Never returns any challenge or secret' twice, adding slight redundancy. Otherwise, every sentence serves a purpose and the structure is logical.

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

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

For a read-only tool with one optional parameter and no output schema, the description fully specifies return fields, usage semantics, security guarantees, and a related well-known resource. It provides an example and covers all necessary context for correct invocation.

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

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

The schema already describes manager_id as 'defaults to the caller.' The description reinforces this with 'Omit manager_id to read your own' and adds an example with empty arguments. With 100% schema coverage, the description adds minimal new semantic detail, 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.

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

The description clearly states the tool reads a manager root's bound public key and lists the specific fields (public_key, alg, kid, bound_at). It also distinguishes itself from sibling tools like federation_key_bind (which binds keys) and federation_key_challenge (which likely involves secrets) by emphasizing read-only and never returning a challenge or secret.

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

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

Provides context: a counterparty verifies signatures, and you can omit manager_id to read your own key. It also hints at alternative resources (full attestation chain at well-known URL). However, it does not explicitly name alternative tools or state when not to use it, though the 'never returns any challenge or secret' clue differentiates it from key_challenge.

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