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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context beyond that: deterministic ordering ('oldest first') and cost behavior ('FREE (no credits)'), which help an agent decide whether to call it.

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?

Two compact sentences with the scoping/ordering fact front-loaded and the sibling pointer at the end. No filler or restatement of the name.

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?

No output schema exists, but for a single-parameter list tool the description covers ordering, cost, and the alternative route, and annotations cover safety. It could note what fields each entry carries, but nothing essential to calling 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?

There is a single parameter with 100% schema description coverage, including a 'Required' flag and a pointer to list_projects for obtaining the ID. The description adds no parameter-level meaning, so the baseline 3 for schema-covered params 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?

States a specific verb and resource ('every disavow entry for a project') and adds scope detail (oldest first) plus an explicit boundary against the export sibling. An agent can distinguish it from add_disavow_entry, remove_disavow_entry, and export_disavow_file without opening any schema.

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?

Names the alternative export_disavow_file and the condition that selects it ('actual Google-format .txt content'), which is clear routing. It does not spell out the inverse use case (inspecting/auditing the raw entry list), but for a list-vs-export pair this is adequate context.

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