refresh_co_changes

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

Annotations already provide idempotentHint=true and readOnlyHint=false. Description adds value by confirming the mutation is idempotent and specifying the return JSON structure ({ status, pairs_stored, window_days }), which is not in annotations.

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 sentences covering purpose, behavior, usage, and return format with no redundant information. Efficient and well-structured.

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?

Covers purpose, usage trigger, mutation, idempotence, and return format. Lacks prerequisites (e.g., git history access) and side effects on other indices, but overall sufficient for a simple tool with good annotations.

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 coverage is 100% with clear parameter description. Description does not add new meaning for the parameter beyond schema, but mentions window_days in the return format, providing indirect context.

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 'Rebuild co-change index from git history' with a specific verb and resource. Distinguishes from sibling tools like get_co_changes (read-only) and reindex (general) by focusing on co-change index and mutation.

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?

Directs 'Use after significant git history changes,' providing clear context for appropriate usage. Does not explicitly list when not to use or name alternatives, but the context strongly implies it is for specific index maintenance scenarios.

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