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

Annotations already establish a safe read-only/idempotent profile, but the description adds substantial operational context: each row carries an active flag, REMOVED/PAUSED keywords with impressions are included as historical data, summary fields cover the whole account, truncated results require next_offset merging, and oversized limits can overflow the client result budget.

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-loads the report purpose, then organizes DATE, PAGING, and NOTE details into tight operational guidance. Every sentence adds useful behavior or parameter meaning, with no filler.

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 complex paginated report with an output schema, the description supplies enough to call it correctly: account-wide summaries, historical inclusion, pagination/truncation handling, zero-impression option, and result-size caution. Missing customer_id explanation is minor given the account-context framing.

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 parameter meaning. It explains period syntax and override behavior, days=0 meaning today, limit max 1000, offset, and include_zero_impressions default exclusion; customer_id is left unexplained, and defaults for days/limit are not stated, so coverage is strong but incomplete.

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+resource: keyword performance and Quality Score, plus flagging low QS and zero-conversion spend. It does not name close siblings such as keyword_quality_report, so an agent must infer differentiation from context rather than from explicit routing.

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 date handling, paging behavior, and when to set include_zero_impressions=true for a complete keyword inventory. It does not explicitly compare this tool against siblings like keyword_quality_report or search_terms_report, so the when-to-use guidance is clear but not fully exclusive.

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