edit_role

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

With no annotations provided, the description carries the transparency burden. It explicitly discloses that this is a write operation, gated behind an environment variable, and that only fields explicitly passed are changed (partial update). This adds important behavioral context beyond what the schema alone provides, though it doesn't discuss permission requirements or failure scenarios.

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 one concise sentence with a leading gate indicator. It is front-loaded with the write warning and immediately states the operation and update semantics. Every word earns its place with no 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?

The tool has an output schema, so return values need not be described. The description covers the core behavior (edit existing role, partial update) and the write gating. It doesn't mention required IDs, but those are in the schema. Overall, it's sufficient for an agent to understand the tool's primary contract, though a bit more context about the role being modified would push it to 5.

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 0%, so the description must compensate. It adds the key semantic that only explicitly passed fields are modified, implying nullable parameters mean 'no change'. However, it doesn't explain individual parameters; while names like 'name' and 'color' are self-explanatory, 'permissions' as a string could be ambiguous without additional context.

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 states 'Edit an existing role' which is a specific verb+resource pair. It clearly distinguishes this from create_role by specifying 'existing' and from edit_channel by targeting roles. The scope is clear and 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?

The description implies usage for modifying existing roles, not creating new ones, and notes it is gated behind DISCORD_MCP_ENABLE_WRITE=1. It doesn't explicitly name alternatives, but the phrasing 'existing role' combined with sibling tool names like create_role makes the appropriate context evident.

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