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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the safety profile is clear. The description adds meaningful behavioral context: the tool returns zero-order terms with high clicks/spend, covers SP and SB programs, and rows carry a program label needed for downstream staging. This goes beyond the annotations without contradicting them.

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?

Two sentences deliver the core purpose, output criteria, program coverage, and a downstream routing hint. No filler or repetition of schema content; the most important decision-relevant information is front-loaded.

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 14-parameter tool with no output schema, the description adequately captures the tool's purpose and return semantics. It could be more complete by noting defaults or date-range behavior, but the schema covers several parameters and the description gives enough for an agent to decide whether to call this tool.

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 71%, so most parameters are already self-documenting. The description adds value by explaining the output semantics ('zero orders'), program coverage (SP + SB), and the program-label nuance that affects how rows should be passed to stage_negatives. This clarifies concepts not obvious from individual parameter descriptions.

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 clearly identifies a specific verb ('Find') and resource ('non-converting search terms with significant spend'), and frames the output as candidates for negative keyword addition. It is distinct from nearby siblings like ppc_negatives, ppc_search_terms, and stage_negatives because it emphasizes zero orders and spend-based filtering.

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?

The description states what the tool is for and gives actionable cross-tool guidance: pass campaign_type=SB to stage_negatives for SB rows. It does not explicitly name alternatives or state when not to use this tool, but the context is clear enough for an agent to select it for negation-candidate discovery.

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