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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the description adds value beyond them by disclosing two real behavioral traits: it never launches a browser or sends anything external, and it fails closed as 'infra_gated' when BrowserMission storage is unavailable. That failure-mode disclosure is genuinely useful for an agent interpreting a result.

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?

Two tight sentences with zero filler, front-loading what is read before the behavioral guarantees. Every clause 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?

For a single-parameter read tool with no output schema, the description covers purpose, side-effect profile, and the failure mode. It does not describe what the returned status values look like, but that is a minor gap given the tool's simplicity.

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?

One parameter with 0% schema description coverage, so the description must compensate. It only restates that missionId identifies the BrowserMission ('by missionId'), adding no format, source, or lookup guidance beyond the schema's type and required flag. Adequate but thin.

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 and resource ('Read the X1-owned status of a BrowserMission by missionId'), which is distinguishable from siblings like summarize_browser_mission_result or draft_browser_evidence_mission. It doesn't explicitly name an alternative sibling, but the scope is unambiguous.

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?

Usage is implied by the definition ('read the status of a mission by id') but there is no explicit when-to-use guidance or routing away from the similar summarize_browser_mission_result sibling. An agent can infer the case but must do so itself.

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