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

Annotations only declare readOnlyHint=false, so the description carries most of the burden and does so well: it discloses cargo/storage consumption, partial-contribution semantics for community missions, the reward categories paid, and the empire-treasury cap behavior including the credits_promised/credits_shortfall/credits_earned response fields. This is exactly the kind of side-effect detail a caller needs before invoking a mutation.

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?

Front-loaded with the core action, then progressively adds mechanics and the edge-case reward-capping note. It is dense and longish for a single paragraph, but nearly every clause conveys operational information, so it earns its size without much waste.

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?

No output schema exists, yet the description explains the notable return fields and the reward-payment edge case, and covers mutation side effects and repeated-call semantics. For a two-parameter mission-completion tool this leaves nothing an agent needs in order to call it correctly.

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 both required parameters (mission_id, session_id), so the schema already documents them fully. The description adds no parameter-specific syntax or format detail, which is the expected baseline when the schema does the heavy lifting.

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?

Starts with a specific verb+resource ('Complete a mission and claim rewards'), and the surrounding detail (delivery objectives, community contributions, reward types) makes it unmistakable versus siblings like accept_mission, decline_mission, or view_completed_mission. An agent can identify the operation without opening the schema.

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?

Gives clear preconditions and call patterns: objectives must be fulfilled, delivery objectives consume cargo at the target base, repeated objectives require combined quantity, and community missions should be called repeatedly as materials are gathered. It doesn't explicitly name alternative tools or state when-not to use this, so it stops short of a 5.

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