Read one role by id, including its complete permission list. Read this before role.update, whose permissions field replaces that list wholesale. Returns the record directly, or null when the id is unknown — an unknown id is not an error here, so null means "no role has that id", never "the call failed".
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Role id (`role_…`) from role.list. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds crucial null-return semantics that annotations cannot convey, ensuring the agent does not misinterpret unknown ids as errors.
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?
Three sentences with no redundancy. The core purpose is front-loaded, and the behavioral caveat about null is concise yet complete.
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 simple get-by-id tool with one parameter, the description covers purpose, usage guidance, and return semantics. The lack of output schema is mitigated by the clear statement that the record is returned directly and permission list is included. Nothing needed for correct invocation is missing.
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% and the parameter 'id' is fully described in the schema (including the format 'role_…'). The description does not add additional parameter-specific meaning beyond what the schema already provides, so baseline 3 is appropriate.
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 ('Read'), resource ('role by id'), and scope ('complete permission list'). It also distinguishes from role.update by noting the wholesale replacement, clearly separating it from the sibling.
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?
Explicitly advises reading this before role.update and clarifies the null behavior ('null means no role has that id, never the call failed'). This gives clear context for when to use and what to expect.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
