Upload media

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

Annotations indicate readOnlyHint=false, destructiveHint=false, but the description adds valuable behavioral context: it only stores media and does not create a lipsync generation, and the file field must be the uploaded ChatGPT file object. This clarifies side effects and constraints beyond the annotated flags. No contradiction with annotations.

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 description is somewhat longer than the top-tier examples, but every sentence contributes: purpose, use case, file constraint, alternative for URLs, and follow-up action. It is well-structured and front-loaded with the main function. No filler, though a bit dense.

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?

Given the simple two-parameter schema and the existence of an output schema, the description covers all necessary context: what it does, when to use it, what it does not do, and how to use the result (pass assetId to create-lipsync). It is fully self-contained for an agent to select and invoke 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 covers both parameters with descriptions (100% coverage), but the description adds extra meaning by specifying that the file field must be the uploaded ChatGPT file object and warns 'Do not pass URL strings here.' This goes beyond the schema's basic property descriptions, reinforcing the intended usage.

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 description opens with a specific verb and resource: 'Upload a user-provided image, video, or audio file to Sync asset storage and return a durable assetId.' It clearly distinguishes from siblings by stating when to use this tool (user uploaded media in chat) and explicitly naming alternatives (assets_create or direct URL to create-lipsync). This is unambiguous and differentiated.

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?

The description provides explicit when-to-use guidance: 'Use this when the user uploaded media in chat and a later Sync tool call should reference it by assetId.' It also gives exclusions and alternatives: 'For public URLs, use assets_create or pass the URL directly to create-lipsync.' This goes beyond vague context to offer actionable selection criteria.

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