Update a skill

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

Annotations only declare readOnlyHint=false and destructiveHint=false; the description adds genuinely new behavioral context, namely that the skill's name and description are re-derived from the new frontmatter (a side effect the caller cannot see from the schema) and the two categories of immutable skills. It stops short of describing auth requirements or whether the prior markdown is recoverable.

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 short sentences, front-loaded with the action, then side effects, then constraints. No filler and no repetition of schema or annotation content.

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?

An output schema exists, so return values need no explanation, and the mutation's preconditions plus its frontmatter side effect are fully stated. Nothing an agent needs in order to invoke this correctly 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 coverage is 67% (skill_id and the account-id header are documented in-schema; markdown only has minLength=1). The description compensates for the undocumented parameter by explaining that markdown is the full replacement body whose frontmatter rewrites name and description — meaning beyond the bare string type.

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 ('Replace a skill's markdown') and clarifies that this is a whole-body replacement rather than a field patch, with skill_id identifying the target. It does not explicitly differentiate itself from siblings like create_skill, delete_skill, or import_skill, but the operation itself is 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?

Covers all three required pieces: the action context (replacing markdown), explicit exclusions ('Skills imported from git are read-only', 'Skills managed by Orchestra cannot be changed'), and the alternative route ('edit the file in the connected repository instead'). An agent knows when not to call this and what to do instead.

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