ads_historical_search_volume

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

There are no annotations, so the description bears the full behavioral burden. It states that this is a read-style lookup returning monthly volume and competition and explicitly warns that no idea expansion happens; however, it does not mention permissions, rate limits, or how missing/invalid keyword IDs are treated. The output schema covers return shape, keeping the gap moderate.

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?

The description is short, front-loads the core behavior and scope in the first sentence, adds an explicit use case, and then lists the args in a scannable block. Every sentence earns its place with no repetition.

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 read-only historical lookup tool with an output schema, the description covers purpose, scope, use case, and all parameters. It could be more complete by naming the sibling keyword-ideas tool or noting account prerequisites, but the agent has enough to select and invoke it correctly.

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%, and this description compensates by documenting all four parameters with useful semantics: customer_id is a 10-digit account id, keywords are an exact list, location_ids get a concrete example ([2840] = US), and language_id gets a constant example (1000 = English). It doesn't explain null defaults or how to discover valid ID values, but it adds substantial meaning beyond the bare schema.

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 opens with a specific verb+resource/operation ('Get historical monthly search volume + competition') and narrows scope to 'a specific list of keywords (no idea expansion)', which clearly distinguishes it from the sibling tool for idea generation (ads_keyword_ideas).

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?

'Use to size demand for exact terms you already have' plus the explicit '(no idea expansion)' tells the agent when this tool is appropriate and implies it is wrong for exploratory keyword discovery. It stops short of naming an alternative tool, so it lacks the fully explicit routing of a 5.

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