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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so safety is covered. The description adds genuine behavioral substance on top: which cryptographic artifacts are validated (Ed25519 signatures, revision hash-chain, arbiter signatures) and the tri-state verdict vocabulary. It does not discuss cost, latency, or failure modes when a room is missing.

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?

Front-loads purpose, then usage, then return shape in a tight progression with no padding. The Args block restating the schema description is mild redundancy but does not bloat the text.

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 an output schema present and annotations covering the safety profile, the description still supplies everything an agent needs: what is verified, when to invoke it, and the branching verdict values. Nothing material is left unexplained.

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% and the single param's text ('Room UUID or full room URL.') is duplicated verbatim in the Args block, so the description adds no meaning beyond the schema. Baseline 3 applies when the schema fully documents the parameters.

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 resource (a room's message and revision chain), then names the exact mechanisms checked: Ed25519 signatures, hash-chain of claim revisions, arbiter signatures. No sibling tool does anything comparable, so it is trivially distinguishable from tools like get_room or read_messages.

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?

Gives a concrete triggering condition ('when the user wants to check that a room's record has not been altered') plus a motivating example ('before relying on a decision reached there'). It does not name an alternative or any exclusion, but no sibling tool overlaps this capability, so the routing guidance is effectively complete.

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