Endorse a mod

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

Annotations already cover the safety profile (write, idempotent, open-world), and the description adds genuinely new behavioral context: the server-side write gate and the fact that the version must match what Nexus knows. It omits failure behavior (e.g. what a mismatch returns) and any auth/user-binding requirements.

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 lean sentences with the core purpose front-loaded, followed by the two preconditions in priority order. No filler or restatement of the title.

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 small mutation tool with no output schema, the description covers the action pair, the write gate, and the version precondition. It leaves minor gaps around error outcomes and how the endorsement is attributed, but nothing an agent needs to invoke 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?

With only 50% schema coverage, the description compensates by clarifying that 'abstain' means withdraw the endorsement and that the version argument must match the version Nexus knows, adding meaning the schema ('required by the API') does not convey. mod_id and game_domain_name remain unelaborated, though the latter carries a schema default.

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 ('Endorse a mod') plus the inverse operation ('withdraw the endorsement'), so the agent knows both directions of the operation. It does not need to distinguish itself from overlapping siblings since no other tool endorses, but it also doesn't explicitly route against alternatives.

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 a concrete precondition (NEXUS_ALLOW_WRITES=true must be set) and tells the agent where to obtain a required value via the sibling nexus_get_mod. It stops short of stating when not to use the tool or what to do on a mismatch.

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