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

With no annotations, the description carries the load and does well: it discloses overwrite-on-resubmit idempotency, that auth is required, and that the call is not billed. It doesn't say whether ratings are visible to others or how failures surface, but the key write-semantics and cost profile are 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?

Three tight sentences, front-loaded with verb, target, and key parameter, then scope, then write semantics, then cost. No sentence is filler; each carries a distinct constraint.

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?

For a three-parameter write tool with no annotations and no output schema, the description supplies the scope, the keying mechanism, idempotency, auth, and billing behavior. Nothing an agent needs to call 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 67% (only `rating` lacks a schema description, and its enum is self-explanatory). The description adds real meaning beyond the schema by explaining that request_id must come from the response of the call being rated, which is the main place an agent could go 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?

Specific verb and resource: rate a prior metered call with thumbs up/down plus optional comment, keyed by request_id. Scope is narrowed to 'compress calls' so an agent knows what is rateable. It does not explicitly contrast with the sibling `feedback` tool, which is the one plausible alternative an agent might confuse this with.

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?

States the operating condition clearly: tell us when a compression was too aggressive or dropped something. Current scope (compress calls only) is stated as a constraint, which prevents misuse. No explicit when-not or named alternative, so it stops short of a 5.

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