Prepare Attachment Download

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, covering the safety profile. The description adds valuable behavioral context: it is a preprocessing step that returns a 'signed URL plan' rather than the file itself, and it requires an existing file_url from specific commands. This goes beyond the annotations, though it doesn't detail the plan's contents or potential 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?

The description is two sentences, front-loaded with the primary purpose and followed by a crisp usage guideline. Every sentence earns its place; there is no redundancy or 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?

The tool is low-complexity (3 params, 1 required) and well-annotated. The description explains the return type (signed URL plan) and the prerequisite (file_url from other commands), which is sufficient for an agent to select and invoke the tool. It lacks a detailed structure of the signed URL plan, but with no output schema and given the simplicity, the description is adequately complete.

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 100%, so the schema fully documents all three parameters. The description's mention of 'file_url from workitem_get or comment_list' adds contextual meaning that the file_url is opaque and sourced from specific commands, which is also in the schema. Since the schema already does the heavy lifting, the description adds only marginal value, consistent with the baseline of 3.

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 description clearly states the tool's function: 'Preprocess an attachment download and return the signed URL plan.' It uses a specific verb ('preprocess') and resource ('attachment download'), and distinguishes from siblings by explicit focus on download versus upload (attachment_prepare_upload) and by referencing file_url from other commands.

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 explicit when-to-use guidance: 'Use this when you already have a file_url from workitem_get or comment_list and need the backend-generated download plan.' This clearly indicates the prerequisite and the intended alternative scenario, though it does not explicitly name upload as an alternative, the sibling tool name and context make it clear.

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