Retrieve a Yandex Audience lookalike segment by its ID, with optional fields, to inspect or reuse similar-audience data in targeting workflows.
Audience: get lookalike by id.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| fields | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not state that this is a read-only operation, what happens on an invalid/missing id, whether it requires specific scopes, or what the response contains.
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?
A single front-loaded sentence with zero waste. It is appropriately short, though this brevity comes at the cost of substance rather than being a virtue of information density.
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 2-parameter retrieval tool with no annotations, no output schema, and 0% parameter coverage, the definition leaves the agent without the parameter semantics or behavioral context needed to call it confidently.
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%, so the description must explain both parameters. It implies the 'id' lookup key but adds no format/type detail, and the 'fields' parameter (a projection/filter list) is completely unaddressed in both schema and description.
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 (get) and resource (lookalike) plus the retrieval key ('by id'), which distinguishes it from the sibling audience.lookalikes.list. It is clear what the tool does, though it never explicitly contrasts itself with the list sibling.
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?
No when-to-use guidance, no prerequisites, and no mention of the lookalikes.list alternative for enumerating lookalikes. The agent must infer usage entirely from the name.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.