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

Annotations already declare readOnly, idempotent, non-destructive, and open-world behavior, so the safety profile is covered. The description adds genuinely new context beyond those flags: the exact signing algorithm (ES256), the JWS format, and the verification endpoint /.well-known/peerlace-keys.json. It does not mention auth requirements or rate limits, keeping it from a 5.

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?

A single front-loaded sentence stating the artifact and its verification path, with no filler or restatement of the title. Every clause earns its place.

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 carries the return-value burden and does reasonably well by naming the returned artifact (an ES256 JWS) and how to validate it. It stops short of describing what claims the JWS payload contains (parties, timestamps, match reference), which an agent assembling a verification flow might want.

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?

Schema description coverage is 100% — match_id and api_key are both documented in the schema, including the nuanced note about when api_key is needed. The description adds nothing about either parameter, so the schema carries the full load and the baseline of 3 applies.

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 states a concrete resource and payload type — an ES256-signed JWS proving a mutual match — which is far more specific than the bare name. It is clearly distinguishable from read-only siblings like list_matches or get_handoff. It does not explicitly contrast itself with any sibling, so it stops short of a 5.

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?

Usage is only implied: the agent can infer it should call this when it needs cryptographic proof of a match, and the description explains how to verify the artifact. There is no explicit when-to-use, when-not-to-use, or named alternative (e.g., list_matches for discovery), so guidance remains inferential.

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