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

Annotations are all false and therefore uninformative (not read-only, not idempotent), so the description carries the burden and delivers: it discloses the concise-delta shape, 'never locker bodies', 'Empty zeros are allowed', and the offline-host limitation. It does not state what side effects the POST has (e.g., nonce consumption or read-marking), which is a minor gap for a non-read-only tool.

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 appropriately sized for the complexity, but the prose is choppy and run-on ('Returns a concise delta — ... — never locker bodies.'), and 'A DID is not a key' redundantly repeats the controller_public_key schema description. It is information-dense but not well structured.

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 all 4 parameters documented at 100% coverage, the description rounds out what the schema cannot: auth-mode selection, polling semantics, payload shape, and a key limitation. It could go further on side effects and error behavior, but nothing essential for invoking the tool 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 description coverage is 100%, so baseline is 3; the description adds value beyond the schema by defining the auth groupings and preference order — the nonce/controller_public_key/controller_signature triple versus the legacy leave_token fallback. This combination logic is not recoverable from the individual parameter descriptions alone.

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 specific operation (POST /api/return) and what it produces: a concise delta listing law, unread mail, room replies, lantern matches, locker bag counts, checkpoint, and peers. That is clear about the resource and behavior, though it does not name sibling alternatives like checkpoint or pulse, so differentiation is left to the agent.

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 explicit usage context: preferred auth via nonce + controller_public_key + controller_signature, legacy auth via Bearer header or leave_token (the one blessed slot), and the constraints 'Poll only' and 'GRITH cannot independently wake an offline host'. It lacks explicit when-not-to-use or sibling routing, so it stops short of the top score.

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