skill_file

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

Annotations already cover read-only, idempotent, and closed-world semantics, so the bar is lower. The description adds real behavioral context beyond them: paths resolve against the skill's own directory, text is returned as text while other content comes back as base64 with a media type, and a single call replaces several round trips. It omits error behavior for missing paths, keeping it from a 5.

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, front-loaded with what the tool does, then path semantics, return format, and the batching instruction. Every sentence carries information and none is redundant.

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?

With no output schema, the description correctly takes on the burden of describing return values (text vs base64 plus media type) and the call-batching model. For a two-parameter read tool this is nearly complete; only failure handling for bad paths is unaddressed.

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 schema already documents both name and paths, including the relative-path semantics and the 8-item cap. The description reinforces the relative-path rule and adds the batching rationale but introduces no syntax or format detail the schema lacks, so the baseline 3 applies.

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 gives a specific verb and resource — reading files that a skill bundles — and scopes it to the skill's own directory, which cleanly separates it from skill_list and skill_run. It stops short of explicitly naming a sibling to disambiguate against, so it lands at 4 rather than 5.

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?

It advises batching ('Ask for every file you need in ONE call') and explains why (a SKILL.md usually points at several), which implies usage after a skill load. However, it never says when to reach for skill_file versus skill_load or skill_list, so the routing guidance is only implied.

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