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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description adds non-obvious behavior: removed keywords are retained as history so they are not regenerated, the pool will not fall below the minimum a run needs, and there is a 25-per-call cap. These are substantive operational facts beyond the structured hints.

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?

Five short sentences, no filler; the primary action and the routing alternative are front-loaded before the secondary facts about history retention, pool floor, and batch size. Every sentence carries distinct information.

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 2-parameter mutation tool with no output schema, the description covers alternatives, batch limits, and retention behavior. It is slightly thin on edge cases (unknown keyword text, partial failure reporting), but annotations already carry the destructive/idempotent profile.

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. The description adds one genuine constraint not present in the schema — 'Up to 25 per call' on the keywords array — while the 'exact text from list_keywords' guidance only restates the schema wording.

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?

Starts with a concrete verb+resource (stop discovery running these searches) and immediately distinguishes itself from sibling tools by naming plan_campaign_change for the broader 'no directories' case. An agent can tell this apart from add_keywords/list_keywords without opening a 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?

Explicitly routes the agent: use this for exact keyword text (as list_keywords shows it), use plan_campaign_change to stop an entire kind of site. Both the alternative and the condition that selects it are stated, so nothing is left to inference.

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