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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful behavioral context by specifying exactly what the tool returns: 'all missions your faction has posted at the current station, including active instance counts and who posted each one.' This goes beyond annotation-provided info and helps the agent set expectations.

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 a single, front-loaded sentence with a parenthetical clarification. Every word earns its place; no fluff or repetition. 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?

The tool is simple (one parameter, read-only, no output schema). The description explains both the action and the result content. It does not mention error conditions or prerequisites (e.g., being docked at a station or belonging to a faction), but these are reasonable omissions for a straightforward list operation. It is sufficiently complete for this complexity.

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%: session_id is fully described. The description adds no additional parameter-specific guidance, but with only one parameter and full schema coverage, the schema does the heavy lifting. 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?

The description uses a specific verb 'List' and identifies the exact resource: 'your faction's posted missions at this station.' This clearly distinguishes it from sibling tools like get_missions or get_active_missions by specifying scope (faction, current station) and adding detail about returned content (active instance counts, who posted each one).

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 provides clear context: this is for listing faction-posted missions at the current station. It does not explicitly mention alternatives or exclusions, but the 'faction' and 'station' qualifiers make the intended use obvious. No explicit when-not-to-use guidance is given, but the context is sufficiently clear.

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