equip_skill

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

With no annotations supplied, the description carries the full burden and does so: it declares the mutation scope (creates/overwrites only the specific skill subfolder, other workspace files untouched), states no network or auth requirements, and describes the failure mode (error with matching suggestions, no disk state change). It also describes the return payload.

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?

Front-loaded purpose sentence followed by labeled When to use / When NOT to use / Returns sections, which makes it easy to scan. Slight redundancy around loading "directly into context" and "for immediate context execution" keeps it just short of optimal.

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 two-parameter mutating tool with no annotations and no output schema, the description covers everything an agent needs: trigger conditions, exclusions, mutation blast radius, auth/network requirements, error behavior, and return contents. Nothing material 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%, so both skill_name (case-insensitive, approximate matching against catalog index) and target_path (default resolution to ~/.gemini/config/skills or .agents/skills) are already fully documented. The description only reiterates the default destination path, adding little beyond the schema.

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+resource pair: "Extracts and installs a specialized skill package from the offline vault into the assistant's active skills folder." It also names the source (offline vault) and destination (active skills folder), which cleanly separates it from siblings like list_vault_skills and get_brand_design.

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?

Provides explicit "When to use" (before writing domain-specific code such as game design, mobile QA, shaders, refactoring) and "When NOT to use" with the named alternative (use list_vault_skills first for discovery). No inference required to pick between siblings.

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