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

Annotations only declare readOnlyHint=true, so the description carries the rest and does so richly: a 20-row cap with total count, rows carrying url/type/key, signed addresses valid for 24 h that load without a session and with any User-Agent, and a documented 403 WAF behavior on legacy media.andresmarder.com for non-browser UAs. This is exactly the operational context an agent needs before calling.

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 core purpose and return shape before the URL/WAF caveats, and each sentence carries real information rather than filler. It is slightly dense and the URL-signing detail spreads across several clauses, but nothing is wasted.

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?

With no output schema, the description compensates by specifying the return shape (up to 20 rows, total count, url/type/key fields) and the lifetime and loadability of returned addresses. Combined with the schema's preview documentation, an agent has everything needed to call and consume the result 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 description coverage is 100%, and the schema itself covers project_id, asset_type's enum, and preview's 512px/4-per-call behavior in detail. The description only restates the optional asset_type filter, adding nothing beyond the schema, so the baseline 3 applies.

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 ('List a project's media assets (image/video/audio) with their URLs') and scopes it to a single project, which is more precise than the title alone. It does not, however, set itself apart from nearby siblings such as lab_list_audio or lab_bilder, which an agent may confuse with this one.

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?

It tells the agent the asset_type filter is optional and gives practical routing advice (fetch with a browser UA, or hand the URL to the user) for older rows. What is missing is any statement of when to reach for this tool versus lab_list_audio/lab_bilder or when not to use it, so usage is only implied.

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