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

With no annotations provided, the description carries the full burden. It discloses idempotency (a key retry-safe behavior), that it does not copy bytes (so it is a reference operation), and the canonical usage scope. It does not mention permissions or error conditions, but the core behavioral traits are well covered, earning a 4.

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 four sentences, each carrying distinct information: purpose, idempotency/no-copy, canonical usage with transcript exclusion, and the parameter requirement. It is front-loaded with the main verb and object, and there is zero fluff.

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 moderate tool with an output schema and 4 parameters, the description covers the essential operational semantics: idempotency, non-copy behavior, canonical usage, transcript routing, and the minimum parameter requirement. It does not explicitly address what happens if both work_id and project_id are provided, but the 'and/or' phrasing implies simultaneous attachment, and the schema already documents each parameter. Overall, the description is complete enough for an agent to call it correctly.

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 100%, so the baseline is 3. The description adds value by clarifying that at least one of work_id/project_id must be passed (a constraint not enforced by the schema, which only requires file_id) and by framing file_id as 'existing Storage object'. This goes beyond the schema descriptions, so a 4 is warranted.

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 action (attach), the object (existing Storage object), and the targets (work item and/or project). It differentiates from siblings by labeling itself the 'canonical artifact attach for blobs and documents' and explicitly excluding transcripts, which distinguishes it from file-related tools.

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 provides clear context: it is the canonical attach for blobs/documents, and it explicitly says transcripts should go to file_* or work_item_files.kind=transcript. It also states the 'at least one of work_id/project_id' requirement. However, it does not name specific sibling alternatives (like storage_move or storage_publish) for comparison, so it falls short of a perfect 5.

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