create_upload_session

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

With no annotations provided, the description carries the full burden for behavioral disclosure. It reveals that the session is 'long-lived', supports appending over multiple calls, returns a session guid plus aws_key/bucket, and requires a follow-up call to set_upload_done. This is valuable context, but it omits potential details like session expiry, cancellation, or permission requirements (e.g., can_upload).

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 three concise sentences. The first sentence states the core function, the second gives when-to-use scenarios, and the third covers the return value and required next step. Every sentence earns its place with no fluff or repetition.

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?

The description effectively compensates for the lack of an output schema by explaining the return value (session guid plus aws_key/bucket) and the critical follow-up (set_upload_done). It provides enough lifecycle context for a typical batch-upload workflow, though it doesn't mention session expiry, cleanup, or prerequisite permissions, leaving minor gaps.

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?

The input schema has 100% description coverage, meaning every parameter already has a clear description in the schema. The tool description does not add additional parameter-level semantics beyond what the schema provides, so the baseline of 3 is appropriate.

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 clearly states a specific action and resource: 'Create a long-lived upload session.' It goes on to explain the session's purpose ('append files to over multiple upload_file / upload_files calls') and distinguishes it from related tools by mentioning grouping in the Mediagraph UI and resume-after-crash capabilities. This makes it unmistakable what the tool does and how it relates to sibling upload tools.

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 gives explicit when-to-use guidance: 'Use this when batch-uploading many files from a script or agent loop, when you want them grouped under one upload in the Mediagraph UI, or when you need to resume after a crash.' It also references the relevant sibling tools (upload_file, upload_files, set_upload_done). However, it lacks an explicit when-not-to-use statement (e.g., for single-file uploads), which would have pushed it to a 5.

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