slack_download_file

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

With annotations already flagging destructiveHint/openWorldHint, the description still adds real context: required OAuth scope, returned saved path, the <file_id>-<name> naming convention, and above all the atomic 'replace only once the new one is complete' overwrite semantics that explain the destructive flag. External files returning external_url rather than downloading is also disclosed.

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 permission need, then the return value and the two constraints that actually change behavior. Dense but each clause earns its place; the line-broken layout is slightly harder to scan than a single tight paragraph.

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-shape detail is optional, yet the description still names the path and external fallback. Combined with the safety annotations, almost everything needed to call correctly is present; only the workspace parameter and the dest_dir default (~/Downloads/slack) are unaddressed.

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 carry the load; it does for dest_dir (must live inside SLACK_FILE_ROOTS, matching slack_upload_file) and implies file_id is the Slack file identifier. The workspace parameter is left completely unexplained, which is the remaining gap.

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 ('Download a Slack file by id to a local folder') and immediately scopes the behavior further by excluding external files such as Google Drive. It is clearly distinguishable from slack_upload_file and slack_file_info by naming the counterpart tool and the external_url fallback.

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 'needs files:read' prerequisite and the SLACK_FILE_ROOTS restriction tell the agent when calling will fail, and the external-file exclusion routes the agent to reading external_url instead. No explicit 'use this instead of X' framing, but the conditional guidance is strong.

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