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

Annotations supply safety profile (destructiveHint=true, idempotentHint=true), and the description adds meaningful context beyond them: the override/replacement semantics of the setting, the consequential behavior ('SHIP merges without asking again') once enabled, and the required missions:write scope. This is real behavioral disclosure, though it doesn't discuss reversibility or rate/permission failure modes in depth.

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?

Three tight sentences, front-loaded with the core action, then scope/override semantics, then the consequence and auth requirement. Every sentence carries distinct information.

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 two-parameter toggle with no output schema, the description covers what the setting does, its scope relative to projects, its behavioral consequence, and the required scope. Nothing needed to call it correctly is missing.

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 both parameters (enabled, issueId) are fully documented in the schema itself. The description adds no syntax or format detail beyond that, so the baseline 3 applies.

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?

States a specific verb (set) plus resource (this mission's auto-merge) and scope (this mission only). It explicitly distinguishes itself from the project-level setting ('replaces the project's auto-merge for it; get_project shows the project's') and from the sibling merge_mission by being a configuration toggle rather than an action.

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?

Clearly frames the context: per-mission override that supersedes the project default, and points to get_project to inspect the project setting. It doesn't explicitly say when to prefer this over merge_mission or when-not to enable it, so it stops short of full routing guidance.

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