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

With no annotations, the description carries full burden. It reveals that results are sorted newest first and, more importantly, details the pagination protocol: when truncated, use modified_before and name_after, and why (timestamps not unique). This is substantial behavioral insight beyond a simple description.

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?

Two sentences, each with a clear job. The first defines the operation; the second explains edge-case behavior. 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?

With 5 parameters and no annotations, the description covers the most complex aspects (ordering and pagination). It leverages the output schema for return format. Minor gaps: max_entries is not explicitly linked to truncation, but it is inferable.

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?

The schema has 0% description coverage, so the description must explain parameters. It explicitly describes modified_before and name_after (pagination, non-unique timestamps), and implies path with 'downloads' example. It does not explicitly discuss session_id or max_entries, but their purpose is evident from context and naming.

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 first sentence clearly states the action ('List files'), the resource ('on a browser session's machine'), and the ordering ('newest first'), with a concrete example ('downloads'). This distinguishes it from siblings like list_agents (agents) and read_file/write_file (content).

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 context: listing files on a session's machine, e.g., downloads, which implies use when you need to see available files. It does not explicitly name alternative tools or exclusion cases, but the scope is clear enough to differentiate from siblings.

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