Assert

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

With no annotations provided, the description carries full burden and does well by disclosing key behavioral traits: it's a polling operation (implies repeated calls may be needed), returns pass/fail status, provides actionable failure details, and includes screenshot URLs for failed steps. It doesn't mention rate limits, authentication needs, or error handling.

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?

Two concise sentences with zero waste. First sentence states the action and resource, second sentence details the return values. Every word earns its place and information is front-loaded appropriately.

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 single-parameter tool with no output schema, the description provides good context about what the tool returns (pass/fail status, failure details, screenshot URLs). It could be more complete by specifying the polling interval or whether this is a blocking call, but covers the essential behavior well given the complexity.

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 100% (run_id is fully documented in schema), so baseline is 3. The description doesn't add any parameter-specific information beyond what the schema already provides about the run_id parameter.

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 states the tool's purpose with specific verbs ('poll', 'returns') and resources ('test run', 'status', 'step-level results'). It distinguishes from siblings by focusing on status checking rather than generating, listing, or initiating runs.

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 usage after a test run has been initiated (since it requires a run_id from assert_run), but doesn't explicitly state when to use this tool versus alternatives. No explicit guidance on when-not-to-use or direct comparison to siblings is provided.

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