ck_failure_clusters

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description aligns with these by indicating a read-only clustering operation. However, it does not add extra behavioral context beyond what annotations provide, such as prerequisites or side effects.

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 concise sentence that front-loads the main action and outcome. Every word is meaningful, with no redundancy or 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?

While the description states the high-level purpose, it does not clarify what 'reusable eval candidates' are, how to interpret the output, or the definition of 'recent' sessions. Given the complexity of clustering and existence of an output schema, more context would be beneficial.

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 75%. The description does not add parameter-specific meaning; project_root and session_id are described in the schema, but same_domain_only and session_limit lack descriptions both in schema and tool description. The tool description does not compensate for the uncovered parameters.

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 verb 'cluster', the resource 'recurring failure modes across recent session traces', and the outcome 'return reusable eval candidates'. It effectively differentiates from sibling tools like ck_trace_packet and ck_experience_index by focusing on failure mode clustering and eval generation.

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 for analyzing recent session traces in the same workspace but provides no explicit guidance on when to use this tool versus alternatives like ck_trace_packet or ck_experience_search. No when-not-to-use or exclusion criteria are given.

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