list_files

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

With no annotations, the description carries the burden and does well: it discloses that files live in a separate store from notes, that results are name/size pairs, that an empty list is a valid non-error outcome, and that 'locked' true means the passphrase doesn't unlock them. It stops short of covering errors, permissions, or pagination behavior for large folders.

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 action and the return shape, then the routing hint, then edge cases. Slight redundancy: the 'files are separate from notes' fact appears in the description and again in the folder schema, and 'Call this to see which files exist' re-states the opening sentence.

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 needn't be explained, yet the description summarizes them anyway and adds the semantic edge cases (empty list, locked) that the schema cannot convey. For a single-parameter read tool, an agent has everything needed to call it and interpret results.

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 100% and the schema already defines 'folder' with the default-space semantics, so the description adds essentially nothing new about the parameter beyond restating that files are separate from notes. Baseline 3 is appropriate where 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?

Opens with a specific verb and resource ('List the files the user has stored in a folder') and scopes the output ('name and size'). It also distinguishes itself from a sibling by stating that 'recall never returns them', which an agent cannot infer from the name alone.

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?

Explicitly sequences the workflow: 'Call this to see which files exist, then fetch_file to retrieve one.' It also rules out the misleading alternative ('recall does not find them'), covering both when-to-use and when-not.

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