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

Annotations already declare read-only, idempotent, non-destructive, so the safety profile is covered. The description adds genuine behavioral context: signing is conditional ("when it has one"), the signature embeds the key, and the receipt reflects the event hash chain head. It does not discuss pagination or failure modes, but for a read-only receipt that is minor.

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?

Three sentences, front-loaded with the core artifact and its contents before branching into signing and usage. Dense but every clause carries distinct information; 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?

There is no output schema, so the description carries the burden of explaining the return value — and it does so thoroughly (contents, signature, key provenance). Combined with annotations covering safety and full parameter coverage, nothing an agent needs to invoke it correctly is missing.

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 coverage is 100% and the single run_id parameter is fully documented in the schema. The description adds no format, length, or sourcing detail beyond the schema's "A run id from rig.run.create," so baseline 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 names the exact artifact produced (a signed statement of a run) and enumerates its contents: project, suite/version, status/outcome, verdicts, event count, and hash-chain head. It also differentiates from the sibling rig.evidence.export by explaining that the signature is what makes this a proof artifact.

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?

"Give this to whoever needs proof of what the run did" states the audience and the situation, and it references related surfaces (rig.evidence.export's manifest, GET /rig/v1/evidence/keys) for key naming. It stops short of an explicit when-not-to-use or a direct either/or against the sibling.

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