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

Adds real behavior beyond annotations: it never proposes broad-match negatives, it emits pre-built add_negative_keywords calls per theme, and it details the language-detection fallback (writing system vs campaign language, no call when unavailable). The restated 'Read-only' duplicates readOnlyHint=true but does not contradict 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?

Front-loaded with the core action and themes, then the output contract. The middle sentence about language detection is dense and parenthetical but still earns its space; overall only minor tightening is 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?

An output schema exists, so return values need no explanation, and the analysis purpose is well covered. However, for a 7-parameter tool with no schema field descriptions, the missing parameter guidance (filters, output format, caps) leaves the definition only marginally complete.

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 0%, so the description must carry the parameter burden. It covers the theme list and implies the 30-day window, but says nothing about detail, render, min_clicks, max_findings, or how to override days — four of seven parameters are undocumented anywhere.

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 ('Group the last 30 days of search terms into negative-keyword candidates') and enumerates the exact themes it detects. An agent can distinguish it from siblings like analyze_waste or add_negative_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?

Makes the workflow clear: it returns 'one ready-to-run add_negative_keywords call per theme,' which routes the agent to the follow-up tool. 'Never proposes broad-match negatives' and 'Read-only' set boundaries, but there is no explicit when-not-to-use or comparison against analyzer siblings like analyze_waste.

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