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

Goes well beyond the annotations, which only declare destructiveHint=true and non-idempotent. The description adds an explicit extension allow-list, hard caps (25 MB/file, 10 files/task), and time-based rules for upload and deletion, which an agent needs to avoid rejected calls.

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 verb and resource, followed by examples, then constraints. Despite its length, every clause (extensions, caps, timing, filename override) carries actionable information with no 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 mutation/upload tool with no output schema, it covers the critical unknowns an agent faces: what is accepted, size/count limits, and the window during which uploads and deletions are valid. Nothing essential is missing.

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 already documents all three parameters. The description only lightly reinforces filename's override behavior, which the schema already states. Baseline 3 is appropriate.

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 ('attach a working file from local disk to an owned task') and backs it with concrete examples (STL/STEP model, spec PDF, reference image). It clearly distinguishes itself from the sibling list_task_attachments by being the write side of attachments.

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?

Gives clear usage context: the worker can download the file, including while deciding whether to accept the task. It also states the operational window (uploads allowed until proof is submitted). It does not explicitly name an alternative tool or state when not to use this one, so it falls short of a 5.

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