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

Annotations (readOnlyHint=false) confirm it's a mutating operation and do not contradict the description. The description adds the key behavioral fact that system categories are protected from modification. It does not disclose other traits such as error handling, idempotency, or side effects, but given the simple nature of the tool, the added constraint provides meaningful transparency beyond the annotations.

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 extremely concise: two sentences plus an Args/Returns breakdown. It front-loads the core purpose and constraints, with no superfluous content. Every sentence earns its place, and the structured format aids quick parsing.

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 2-parameter tool with no nested objects and no output schema, the description covers the essential context: what it does, the system category restriction, parameter meanings, and a general return type. It does not specify error cases or permission requirements, but these are not critical for a simple update tool and the existing info is sufficient for an agent 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?

Schema description coverage is 0%, so the description must explain parameters. It does so effectively: category_id is described as 'the category ID to update' and name as 'new category name (max 50 chars)'. This adds value beyond the bare schema by clarifying purpose and validation. It omits that name is optional (though schema shows default null), but this is a minor gap.

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?

Clearly states the action: 'Update a user-created category.' The verb 'update' plus the resource 'category' is specific. It also distinguishes from create/delete by saying this is for existing user-created categories, and adds the constraint that system categories cannot be modified, which sets scope apart from potentially similar tools.

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?

Implicitly indicates usage: update user-created categories, and explicitly warns that system categories cannot be modified. However, it does not mention alternatives (e.g., create_category for new categories, delete_category for removal) or provide explicit when-to-use vs. when-not-to-use guidance beyond the system category restriction. This leaves some inference to the agent.

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