add_attachment

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

With no annotations, the description carries the full burden and does well: it discloses copy (not move) semantics, that only supported images are accepted, that the inbox is fixed, and that stale revisions are rejected (optimistic-concurrency behavior). It omits error/response behavior and permission requirements, keeping it from a 5.

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?

Three tight sentences, front-loaded with purpose then source rules then the revision requirement. No filler, and the most important constraint is stated first.

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 6-parameter mutation tool with no annotations, no output schema, and 0% schema coverage, the description covers the critical source and concurrency rules but says nothing about caption, experienced_at, id, or the outcome of the operation.

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 compensate. It adds real meaning for source_path (delivered by the channel message) and attachment_token (from list_pending_attachments), and explains expected_revision, but leaves id, caption, and experienced_at entirely undocumented.

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 (copy), resource (one supported image), source (fixed attachment inbox) and destination (an existing vault entry). This clearly distinguishes it from read-only siblings like get_attachment and list_pending_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?

Explicitly tells the agent which sources are acceptable (a path from the current channel message, or a token from list_pending_attachments) and warns against invented paths, naming a sibling tool. It also gives the precondition of supplying the revision from the latest read. It does not spell out when not to use it, so it falls just short of 5.

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