tarn_last_root_causes

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

No annotations are present, so the description bears full responsibility. It claims to be the 'fastest failures-first read' but does not disclose any side effects, authentication needs, rate limits, or error conditions. For a tool with no annotations, more behavioral detail is expected.

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?

Three concise sentences: purpose, use case, and equivalence. No filler, every sentence adds value.

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 only 2 parameters, no output schema, and no annotations, the description covers the core purpose and usage well. It lacks explicit output format details, which would be helpful since no output schema exists.

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 covers both parameters (cwd, run_id) with descriptions, achieving 100% coverage. The tool description adds no additional parameter-specific meaning beyond what the schema already provides, so baseline score of 3 applies.

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?

Explicitly states it returns root-cause failure groups (NAZ-402), contrasting with the wider failures envelope. Includes a specific verb ('Return') and resource, and distinguishes from sibling 'tarn_last_failures' by mentioning it is the fastest failures-first read.

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?

Provides context for use ('agent planning a fix') and gives an equivalent CLI command. However, it does not explicitly state when not to use it or directly contrast with alternatives like tarn_last_failures.

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