api_notes

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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds the specific constraint that it should be read once per session, which is useful behavioral context. It also clarifies the content scope ('behavior the official docs do not state'), which goes beyond annotations. No contradiction with annotations.

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 a single sentence that is concise and directly states the purpose and the usage hint. It is front-loaded with the topic and ends with the session constraint, making it efficient and easy to parse. There is no wasted wording.

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?

Given the tool has no parameters, a clear purpose, and an output schema (which likely describes the returned notes), the description is sufficient for an agent to know when and why to call it. It could mention the nature of the notes more explicitly, but the current description combined with the output schema is adequate for a simple read-only informational 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?

The tool has zero parameters, so the schema fully covers them (coverage 100%). With 0 params, the baseline is 4, and the description does not need to add parameter-specific information. It correctly focuses on behavior and usage rather than parameter details.

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 the tool as providing undocumented Amazon Ads API behavior, and 'Read once per session' implies a retrieval action. It is specific about the resource (API behavior notes) and distinguishes itself from sibling tools that perform concrete operations like get_plan or list_profiles. However, it lacks an explicit verb like 'retrieve' or 'fetch', so it is clear but not maximally explicit.

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 phrase 'Read once per session' gives a clear timing instruction, implying it should be used at session start. However, it does not mention alternatives or conditions under which to use this tool versus the many sibling tools, nor does it state when not to use it. The guidance is implied rather than explicit.

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