Save a skill

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

Annotations already indicate readOnlyHint=false, so it is clear this is a write operation. The description adds that it 'merges into the workspace Skills library', which is useful context about the state change. It does not disclose idempotency or behavior on duplicate names, but with annotations covering the basic write nature, this is acceptable.

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 two sentences, with the purpose front-loaded and concrete examples provided. It is efficient and contains no filler or redundancy.

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 description adequately explains what a skill is, how to formulate its directive, and how it integrates with the skills library via list_skills. For a simple two-parameter tool with no output schema, this provides sufficient context for an agent to call it correctly. Minor gaps, such as duplicate-name behavior, are not critical.

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%, with both name and directive fully described. The description adds a general guidance to 'distill an imperative, self-contained directive' which reinforces the schema but does not introduce new parameter-specific information. Baseline 3 is appropriate since the schema does the heavy lifting.

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 clearly states the tool saves a reusable custom SKILL, provides concrete examples (hook formula, UGC recipe, compliance rule, persona), and differentiates it from sibling tools like list_skills, get_skill, and delete_skill by referencing the workspace Skills library. It uses a specific verb+resource construction.

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 gives solid context: it is the save operation for reusable skills, and it mentions list_skills as the way to view built-ins and custom skills, which implies when to use it relative to viewing. However, it does not explicitly state when not to use this vs. other save tools (e.g., save_playbook) or provide exclusion conditions.

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