Read Yandex Audience: segments and reach

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

Annotations already mark readOnlyHint, but the description goes well beyond by explaining that only processed segments are visible, that IDs differ from Audience ids, that no_data=true means counting is incomplete, and that totals live in the stat response rather than the segment object. These are non-obvious behaviors an agent needs to interpret results correctly.

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 dense but every sentence carries essential information: action semantics, tricky data-status behavior, ID mismatch warning, credential requirements, and sibling routing. It is front-loaded with the core purpose and reads in a logical flow without filler.

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?

Despite lacking an output schema, the description sufficiently explains the return semantics for both actions, including status values, no_data behavior, and where totals live. It also covers prerequisites, credentialing, and the alternative tool for writes, making the definition complete for correct selection and invocation.

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?

Input schema coverage is 100% with enum and descriptions for both parameters, so the baseline responsibility is already met. The description adds meaningful context by clarifying what each action does with the parameters and explaining that stat requires segment_id and that totals appear in the stat response, not the segment object.

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 explicitly names the API, states it is read-only, and enumerates two actions with specific verbs: 'segments' lists segments and 'stat' answers reach/affinity. It also distinguishes itself from the write sibling direct_audience_segments, so an agent can immediately tell what this tool is and is not.

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 clearly states when to use the tool: for reading audience segments and stat data. It explicitly routes the write case to direct_audience_segments, warns that retargeting conditions should be verified via retargetinglists rather than computation, and provides the required credential setup command.

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