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

Annotations already declare this is a non-destructive, non-idempotent, closed-world write. The description adds genuinely useful behavior beyond that: the URL is single-use, bytes must be PUT to the returned URL, JPEG/PNG/WebP are auto-resized, and only one upload per role per guest session is allowed. It omits URL expiry/auth details, keeping it below a 5.

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 context tag 'For Codex/local files' is front-loaded and each following sentence adds a distinct constraint (single-use URL, no disclosure, format support, quota, no try-on). The 'do not disclose that capability' instruction is unusual but still short and purposeful.

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?

An output schema exists, so the description needn't document the response, and it still usefully refers to the 'returned URL'. Given one enum parameter and clear annotations, the description covers the call mechanics, quota, and format handling; only URL lifetime and the credential/context requirements for the PUT are absent.

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 0%, so the description has to carry the burden for the single `role` enum. It does map the enum values to meaning ('personal photo or product image') and notes the one-per-role limit, which compensates partially, but it never explicitly defines which enum value corresponds to which scenario or confirms the parameter is required.

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 names a specific action (reserve a single-use HTTPS PUT upload) and the resource scope (personal photo or product image for a guest session), and it explicitly rules out try-on generation, which separates it from create_try_on/create_trifit_try_on siblings. It never names prepare_trifit_upload, so the distinction from that near-twin is left implicit.

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?

'For Codex/local files' and 'At most one upload per role per guest session' imply when this applies, and the closing sentence excludes try-on usage. However, there is no explicit guidance on choosing this over prepare_trifit_upload or on what happens if the one-per-role quota is already consumed.

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