Update pull request

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

With no annotations provided, the description must disclose behavior itself. It reveals that only open PRs can be updated and that fields are partially updated, which is useful. However, it does not mention permissions, response format, or side effects like what happens when changing the destinationBranch.

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 two sentences long, front-loaded with the primary purpose, and every sentence provides useful guidance without redundancy. It is concise 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?

Given the tool's moderate complexity, no output schema, and no annotations, the description covers the essential purpose, update semantics, and relationship to a sibling. It could mention response details or parameter-specific behaviors, but the provided information is sufficient for an agent to use the tool correctly in most cases.

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 schema covers 71% of parameters with descriptions, so the baseline is near 3. The description adds meaningful semantics by stating that only provided fields are changed and omitted fields are left as-is, which applies to all parameters and clarifies the PATCH-like behavior.

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 an open pull request,' with a specific verb and resource. It also distinguishes this tool from the description-only sibling by directing users to bb_update_pull_request_description for description-only edits.

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 gives explicit guidance on when to prefer the sibling tool for description-only edits, which is a clear exclusion. It also explains the partial-update behavior ('Only the provided fields are changed; omit a field to leave it as-is'), helping the agent decide which fields to pass.

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