vfs_inspect

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

With no annotations, the description carries the behavioral burden: it correctly declares the operation read-only and enumerates what each action does, which is genuine safety context. However, it omits return-shape behavior, the max_tokens=1250 cap, and any auth or error semantics. Adequate but well short of full disclosure for a no-annotation tool.

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 with the read-only framing, then tightly structured into action glossary, USE WHEN, and DO NOT USE blocks. Every clause earns its place; no filler.

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 7-parameter, 6-action tool with no output schema and no annotations, the description is nearly sufficient: action purposes and usage boundaries are covered. The gap is that per-action return format and the max_tokens behavior are never described, which matters given the absent output schema.

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 0%, so the description must compensate, and it largely does: every action enum value is glossed, and 'symbols (exact/prefix symbol lookup)' plus 'read (line range)' imply mode, query, start_line, and end_line. Only target and the max_tokens ceiling are left unexplained, so it adds real value over the bare 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 read-only verb on a virtual file system and enumerates all six action modes (tree, skeleton, read, symbols, grammar, resolve) with a parenthetical meaning for each. The 'DO NOT USE: to write' clause cleanly separates it from the sibling vfs_mutate. An agent can distinguish purpose without inspecting anything else.

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?

Explicit 'USE WHEN' list covers orienting, reading code, fetching folded content, symbol lookup, and grammar inspection; 'DO NOT USE' excludes writing and running tests. This is the strongest form of routing guidance, leaving nothing to inference.

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