update_pr_branch

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

Annotations already indicate idempotentHint=true (safe to retry) and destructiveHint=false. The description confirms mutation but adds no new behavioral context, such as what happens if upstream changes conflict or how expected_head_sha affects behavior. The agent gains little beyond the 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?

The description is a single concise sentence that states the basic purpose, but it is overly minimal. While it earns its place by being to the point, it lacks structure and omits critical information that could be added without significant length.

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 tool's complexity (4 params, output schema) and lack of parameter descriptions, the description is incomplete. It does not explain the role of expected_head_sha, the behavior on failure, or the return value, even though an output schema exists. The agent would need to infer or experiment.

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?

With 0% schema description coverage and 4 parameters, the description should explain at least the required parameters (repo_owner, repo_name, pr_number) and the optional expected_head_sha. It offers no parameter details, leaving the agent to rely solely on parameter names.

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 'Updates the pull request branch' and specifies 'with the latest upstream changes,' indicating a unique operation among sibling tools like merge_pr or create_pr. However, it does not explicitly differentiate from siblings or clarify what 'updates' entails (e.g., rebase vs. merge).

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 provides no guidance on when to use this tool versus alternatives (e.g., merge_pr, get_pr_diff). There is no mention of prerequisites, typical scenarios, or exclusions, leaving the agent to infer usage from the name alone.

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