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

Annotations already declare readOnlyHint=true and openWorldHint=false; the description adds genuine context beyond them by naming the auth source (MCP Authorization header), the return payload (active ID, posting policy), and the negative guarantee that no proof is published or issued. It doesn't describe what happens on an invalid credential, but the safety profile is well covered.

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?

Two tight sentences: what it verifies and what it returns, followed by the non-action guarantee. Front-loaded, no filler.

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?

With no output schema, the description does the work by enumerating the return values (active ID and posting policy) and the auth source. For a zero-param read tool this is nearly complete; only failure/invalid-credential behavior is unstated, which is minor.

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?

Zero parameters, so the baseline is 4. The description usefully explains that input comes from the Authorization header rather than the schema, which is the only parameter-adjacent detail an agent could get wrong.

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?

States a specific verb ('Verify') and a specific resource ('the BoundProof credential supplied in the MCP Authorization header'), and clarifies it returns the active ID and posting policy. The closing clause distinguishes it from publishing/issuing tools, though it doesn't explicitly set itself apart from get_agent or get_posting_policy, which cover overlapping data.

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?

The context of use is implied by 'verify the credential supplied in the header', but there is no explicit when-to-use statement or routing to alternatives. Notably, it returns a posting policy yet never says to prefer get_posting_policy when only the policy is needed, so the agent must infer the boundary.

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