list_downloads

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

With no annotations, the description carries the full burden and does so thoroughly: it is read-only, "asks nobody" (no prompt/permission interaction), does not open the browser, and is safe during a takeover. It also discloses error-state behavior — blocked or failed downloads leave no file and are excluded from the list.

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?

Purpose and ordering are front-loaded in the first sentence, followed by return shape, exclusion rule, and side-effect profile. Prose is slightly chatty ("it asks nobody") but every sentence contributes; nothing is 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 zero-parameter read tool with an output schema, the description covers everything an agent needs: what it lists, ordering, what is omitted, and that it is safe/non-interactive. Return values are already covered by the output schema, and the description still summarizes the entry fields.

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 tool takes zero parameters, so per the baseline rule a 4 applies. The description adds nothing to explain (nothing to explain), but it does define the returned entry shape, which is extra value.

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 and resource ("List the files this session has downloaded") plus ordering ("oldest first"). No sibling does anything similar, so it is trivially distinguishable from read_draft, screenshot, tabs, etc.

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?

No explicit when-to-use/when-not statement, but it gives actionable routing context: it "works during a takeover," which tells the agent this tool remains callable in a state where most siblings are blocked. No alternative tools exist to name, so the only gap is the absence of an explicit trigger phrasing.

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