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

Annotations cover safety (destructiveHint=false, idempotentHint=true) but the description adds context annotations cannot: no credit cost, the concrete outcome of a duplicate save ('returns the existing saved ad'), and full authentication requirements (OAuth prompt or Bearer acd_live_ key with a settings URL).

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 purpose and source, then the pass-through rule, cost, idempotency, and auth in short clauses. Every sentence carries distinct decision-relevant information; nothing is repeated from the schema or annotations.

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 narration, and the description closes the remaining gaps: cost, idempotency behavior, auth setup, and the input hand-off rule. Nothing an agent needs to invoke this correctly is missing.

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 100%, so the baseline is 3, and the nested row fields are documented inline. The description goes beyond that by prescribing how to populate the parameter ('Pass the row exactly as returned'), which prevents the agent from mutating or trimming fields.

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 ('keep one ad ... on the account') and names the exact source sibling (search_competitor_ads) plus the downstream use (decoded and placed on a board). An agent can distinguish it from list_saved_ads and get_saved_ad 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 says to pass the row exactly as returned from search_competitor_ads, which tells the agent the precondition for calling it. It does not, however, explicitly rule out alternatives or state what to do if the ad was not sourced from that tool.

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