git_branch

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

No annotations are provided, so the description carries the full behavioral burden. It does disclose the key side effect that the working tree HEAD changes ('checks out'), but omits whether it fails on an existing branch, whether uncommitted changes are affected, and whether it returns an error or a new branch ref.

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?

A single, efficiently front-loaded sentence with no wasted words. It is terse to the point of leaving behavior unexplained, but structurally there is nothing to trim.

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?

For a state-mutating git operation with zero annotations and no output schema, the description is too thin: it says nothing about failure modes, preconditions, or the resulting repository state beyond the checkout. The schema covers parameters, but the behavioral contract for the mutation is largely absent.

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 100%, so branchName, cwd, and startPoint are already documented. The description mentions none of them, adding nothing beyond the schema, but the baseline of 3 applies when the schema does the heavy lifting.

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 states a specific verb+resource ('Creates and checks out a new branch') that clearly distinguishes it from repo-mutating siblings like git_commit, git_merge, and repo_write_file. It captures both the creation and the checkout side effect. It does not, however, contrast with any branch-adjacent alternative.

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?

There is no guidance on when to use this tool versus alternatives, nor any stated preconditions (e.g., whether a branch already exists, whether uncommitted changes block the checkout). Nothing tells the agent when-not to call it.

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