Manage Firefox browser downloads: fetch a file by URL, list existing items using search queries, or cancel active transfers.
Downloads operations.
Args: op: "download" | "list" | "cancel". url: For "download", the URL to fetch. filename: Optional output filename. query: For "list", a downloads.search query dict.
| Name | Required | Description | Default |
|---|---|---|---|
| op | Yes | ||
| url | No | ||
| query | No | ||
| filename | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations and no output schema, so the description carries the full burden and delivers little: it does not say where files land, whether downloads persist across sessions, whether 'list' returns only the current session's entries, or what happens to partial files on cancel. There is also no mention of permissions or rate limits.
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?
Very terse and front-loaded, with a compact arg list that is easy to scan. The redundant header 'Downloads operations' wastes one line, but nothing else is padded.
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?
Four parameters at 0% schema coverage with no annotations and no output schema leaves the definition too thin: an agent cannot tell how to identify a download to cancel, what 'list' returns, or where downloaded content is written. The op-to-param mapping is the only real substance.
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 0%, so the description must compensate, and it does partially by binding url/filename to 'download' and query to 'list'. However, 'cancel' has no documented identifier parameter even though cancelling a transfer clearly requires one, and no accepted query keys or filename constraints are given.
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 header 'Downloads operations' is vague, but the op enum (download, list, cancel) makes the resource and the three concrete actions recoverable. No sibling tool covers downloads, so differentiation is not the issue here; the gap is that the tool's core behavior (fetching to disk? tracking in-progress transfers?) is only implied.
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 maps parameters to operations but never states when to reach for this tool, whether 'download' blocks until completion, or how 'cancel' selects its target. Usage must be inferred entirely from the op names.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.