ism_coverage_impact

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

The description provides rich behavioral details beyond the readOnlyHint annotation: it explains the three output buckets (re_review, removed_upstream, new_uncovered), default behaviors for target_version and project_path, and that it reads the manifest like ism_coverage_read. The annotation is consistent (readOnlyHint=true, 'Never writes').

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 concise and well-structured: it starts with the core purpose and read-only nature, then details the output buckets, defaults, and contextual usage. Every sentence adds value without redundancy.

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 output schema exists (so return values are not needed in description), the description adequately covers the tool's behavior, usage context, and parameter defaults. The only minor gap is no mention of the limit parameter, but since it defaults to 50 and has an output schema, this is acceptable.

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 has 0% description coverage, so the description must compensate. It adds meaning for target_version (defaults to scope.baseline_version or active version) and project_path (walks up from cwd when omitted), but does not describe the limit parameter. Coverage is partial, warranting a score of 3.

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 it reports impact of a newer ISM version on coverage, and explicitly says 'Never writes.' It distinguishes itself from sibling tools like ism_coverage_upsert (writes) and ism_coverage_read (reads current state).

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 explains when to use it: 'Run this after ingesting a new ISM release' and what to do next: 'curate the buckets with ism_coverage_upsert.' It also mentions default behavior for target_version and project_path, but does not explicitly state when not to use it.

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