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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds real value beyond them: 'Sends nothing' clarifies no outward side effects, and 'Ones nobody has searched yet go first on the next run' discloses queue-ordering behavior not visible in annotations or schema.

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?

Four short sentences, front-loaded with the verb and examples, then limits, then scheduling behavior, then no-send clarification. Every sentence carries information; only minor stylistic trimming would be possible.

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 non-destructive write tool with no output schema, the description covers purpose, limits, side-effect-free behavior, and queue semantics. What it omits (how the added keywords are confirmed back, whether duplicates are rejected) is minor given idempotentHint=true.

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%, so the baseline is 3, but the description adds constraints the schema lacks: the 25-per-call cap and the 2-9 word length bound. That materially constrains how the agent populates both 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 (Add) and resource (Google search keywords for discovery), with two concrete examples that make the intent unmistakable. An agent can distinguish it from list_keywords and remove_keywords 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?

Explains the context clearly ('search that should turn up sites that could link to this one') and gives hard limits (25 per call, 2-9 words). It stops short of naming alternatives like remove_keywords or list_keywords, so there is clear context but no explicit when-not guidance.

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