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

Goes well beyond the annotations: it discloses that existing media is replaced, that all links are validated before any stored state changes (atomicity), per-type format/size ceilings, a 20-second fetch timeout, the specific failure code `422 media_url_invalid`, and a 10-request/minute per-key budget. These are exactly the risk factors an agent needs for a destructive, open-world write.

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: the first sentence states the action and the replacement semantics, then constraints follow in decreasing relevance (validation, formats, errors, rate limit). Dense but nearly every clause carries operational information; a small amount of overlap between the title line and the opening sentence.

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 destructive write with no output schema, it covers failure modes, atomicity, and rate limits well. The remaining gap is what the call returns on success (media objects? the updated saved reply?) and whether the replacement is reversible, neither of which is stated anywhere.

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 already 100%, so the baseline is 3; the description adds real meaning by tying cardinality to intent (one file vs. up to 10 ordered images for an album) and by attaching format and size limits to the link values. agent_id and saved_reply_id error semantics are left entirely to the schema.

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 ('Put media on a saved reply'), plus the operative qualifier 'from links' and 'Replaces the saved reply's media', which makes the mutation semantics unambiguous. It does not name any sibling (e.g. import_attachment_media, replace_saved_reply, create_upload) to explicitly differentiate, which keeps it from a 5.

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 concrete conditions for use: links must be https, public, no redirects, resolved within 20 seconds, or be the `url` of a Mojeeb upload of this agent — which effectively states the two valid input sources. It never says when to prefer another tool (e.g. direct upload) or when not to call it, so no explicit alternative routing.

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