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

With no annotations provided, the description carries the full burden. The verb 'Fetch' clearly implies a read-only operation, and the description further discloses what the output will contain (top matched threads, relevance scores, report link). It does not mention auth, rate limits, or error handling, but for a simple retrieval tool, the behavioral profile is reasonably transparent. The description adds value by explaining the return value structure.

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, well-structured sentence that front-loads the verb 'Fetch' and concisely conveys the tool's purpose and output. Every word earns its place, and there is no redundancy or filler. It is appropriately sized for the tool's simplicity.

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?

The description is complete for a simple retrieval tool: it explains the input (slug from find_buyer_threads) and the output (top threads with scores, plus link to full report). It does not elaborate on error cases or pagination, but given the tool's low complexity and lack of output schema, the description covers the essential context. It could be improved by mentioning what happens if the slug is invalid, but this is not a significant gap.

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 input schema fully describes the only parameter 'slug' as 'The run slug returned by find_buyer_threads.' The description repeats this by saying 'a find_buyer_threads run' but does not add any additional semantic details beyond what the schema already provides. With 100% schema coverage, the description does not need to compensate, so a baseline score of 3 is appropriate.

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 uses the specific verb 'Fetch' and identifies the resource as 'the results of a find_buyer_threads run', clearly stating what the tool does and distinguishing it from siblings like find_buyer_threads (which creates the run) and other unrelated tools. It also specifies the output content (top matched threads, relevance scores, link to full report), leaving no ambiguity about the tool's purpose.

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 implies the tool should be used after running find_buyer_threads by referring to 'a find_buyer_threads run' and expecting a run slug. This provides clear context for when to use the tool. However, it does not explicitly mention when not to use it or name alternatives, though the sibling list makes the relationship obvious. This is a clear context without exclusions, meriting a 4.

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