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

The description adds substantial behavioral detail beyond the annotations: it enumerates enforced checks, reveals the M3 soft-block behavior tied to the pre-merge risk score, explains how confirm_high_risk overrides it, and specifies the return shape. The destructiveHint is consistent with the merge action, and no contradiction exists.

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 tight sentences with zero filler. It front-loads the core purpose ('Merge an open PR'), then packs behavioral caveats and return information in a logically ordered, scannable way.

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?

Even though there is no output schema, the description explicitly includes the return shape {merged, sha?, reason?, riskScore?}. It also covers prerequisites, gate checks, and the risk-override condition, giving an agent enough context to invoke the tool correctly and interpret results.

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 100% for all four parameters, so the baseline is 3. The description adds meaningful semantics for confirm_high_risk by explaining the M3 risk-score soft-block and the bypass behavior, going beyond the schema's simple 'bypass the M3 risk-score soft-block' phrasing. The other parameters are self-explanatory and require no extra description.

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 opens with a specific verb and resource: 'Merge an open PR.' It clearly distinguishes this tool from siblings such as gluecron_close_pr, gluecron_create_pr, and gluecron_open_draft_pr by focusing on merging an existing, open PR and the checks involved.

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 clear context on when to use the tool: for merging an open PR that must satisfy the same checks as the HTTP merge flow. It does not explicitly name alternative tools or state when not to use it, but the context is specific enough for an agent to select it appropriately among siblings.

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