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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so the trailing 'Read-only' is redundant, but the description adds genuine value by describing the shape of the response (typed findings, per-finding cost, paired remediation call). It doesn't cover cost/rate characteristics or how thresholds interact, but it exceeds what the annotations convey.

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?

Three tight sentences, front-loaded with the diagnostic scope before the return shape. The trailing 'Tools revision: 5c9bea8f.' is versioning noise that doesn't help tool selection.

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 the return contract is covered and the description's summary of findings is a bonus. The real gap is that a 6-parameter analysis tool ships with zero parameter documentation anywhere, leaving the agent to guess at window length, sensitivity thresholds, and output volume.

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% across all 6 parameters, so the description is the only place meaning could be added — and it adds none. Nothing explains what `days`, `min_clicks`, `max_findings`, `detail`, or `render` do or how they change the findings; the two enums are the only self-documenting signals.

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?

The description states a specific verb+resource in concrete terms: zero-converting search terms/keywords, broad match on manual bidding, campaigns under 1.0 ROAS. An agent can tell this apart from the broad diagnostic siblings (full_audit, bidding_audit, analyze_search_terms) because the scope is explicitly 'spend with nothing to show for it' and the outputs are enumerated.

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?

It gives clear context for when to reach for this tool (wasted spend diagnosis with a remediation attached), and the 'exact negative-keyword or pause call that fixes it' tells the agent what to do next. It stops short of naming alternatives or exclusions, e.g. when to prefer analyze_search_terms or bidding_audit instead.

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