git_fetch

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

The description discloses key behaviors: it updates remote-tracking branches, does not change the working tree, and describes the return format ('Fetched N refs from 'origin'.' followed by per-ref lines). The annotations provide no safety hints, so the description carries the full burden and meets it.

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: four sentences covering purpose, usage, exclusions, and return value, with a 'Best for:' section. Every sentence earns its place with no redundant information.

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?

Despite minimal annotations and no output schema, the description is complete for a fetch tool. It covers what it does, when to use it, what it doesn't do, and what the return value looks like, along with next steps (git_log or git_diff).

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 100% parameter description coverage, so the description does not need to add much. It references prune=True in context but does not meaningfully expand on the schema's already clear parameter descriptions.

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 action: 'Fetch refs from a remote (default origin) without merging, updating remote-tracking branches.' It uses a specific verb and resource, and distinguishes itself from git_pull and git_push by noting it does NOT change the working tree.

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?

Explicit guidance is provided on when to use this tool: 'Use this to see upstream changes before deciding to integrate them' and alternatives: 'use git_pull to fetch and integrate, or git_push to send local commits.' It also mentions pruning stale branches with prune=True.

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