Github Update Pr

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

Annotations already indicate mutability (readOnlyHint=false) and idempotency (idempotentHint=true), but the description adds crucial behavior: partial update semantics, labels requiring a separate call, and no special mention of destructive actions. It even discloses that the 'mcp' tracking label is not re-added, which is valuable beyond 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 three sentences with zero redundant words. It front-loads the primary purpose, then vital semantics (partial updates, labels requiring a second call). Each sentence earns its place.

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?

With 8 parameters and an output schema present, the description covers the critical behavioral nuances (partial updates, label handling) that an agent needs to avoid incorrect calls. It doesn't mention required parameters (repo_owner, repo_name, pr_number) but these are obvious from the schema. It also doesn't detail return format, but the output schema presumably does, so no gap.

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 63%, and the description adds meaning beyond the schema by explaining the partial update default (omit to keep current) and the special handling of labels (pass [] to strip). This compensates for the 37% gap, and the description directly clarifies the null-default behavior for each mutable field.

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 it updates an existing pull request, and the field-level detail (title, body, etc.) is specific. It also implicitly differentiates from siblings like github_update_pr_branch (updates branch rather than PR fields) and github_create_pr.

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 explains partial update behavior and explicitly mentions that labels require a second call, steering the agent away from trying to set labels in this call. It doesn't explicitly name alternatives like github_set_pr_draft or github_update_pr_branch, but the context is clear enough.

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