Upload file

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

Annotations only say readOnly=false, openWorld=true, idempotent=false, destructive=false. The description goes far beyond that: the returned upload_url is one-time/non-idempotent, the PUT requires plain curl and NO api key, the resulting file_url arrives in the same response, CDN upload limits apply, and there is no base64 fallback. It also discloses the security constraints (only user-selected files, never third-party hosts).

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 core purpose and the local-file recipe are front-loaded well, but the entry is unusually long and repeats itself ('never local paths or inline data' vs 'There is no base64 option: never re-encode...' and the two separate warnings about third-party hosts). The inline curl block and caps-lock warnings are justified for a safety-critical tool, yet the whole could be trimmed without losing instruction.

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?

There is no output schema, so the description carries the return-value burden and does so — it names upload_url and file_url and says the latter comes back in the same response and is passed onward to the generation tool. Combined with mode selection, security rules, and upload limits, an agent has everything needed 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, but the description adds what the schema cannot: the mutual-exclusion logic among the three optional params and the different return value each mode yields (upload_url for content_type vs file_url). It reinforces the MIME pattern with concrete examples.

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 first sentence states a specific outcome — 'Get a public https URL for a file' — and immediately ties it to the consumer tools ('the generation tools accept ONLY public https URLs'). This cleanly separates it from the generate_*/edit_* siblings that consume the URL rather than produce it.

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 explicitly routes all three invocation modes: content_type for a local file, url for something already online, file_path for reading this server's own disk. It also states the alternative is not viable ('never local paths or inline data'), and adds a security rule about which files may be uploaded and which hosts are off-limits.

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