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

With no annotations, the description carries the full burden and does well: it discloses rate/size limits, that a signed URL is returned, that the PUT must use exactly the returned headers (with a concrete curl example), and the already_stored idempotency short-circuit. Minor gaps remain (URL expiry, error behavior on exceeding limits), keeping it just short of exhaustive.

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?

Content is dense and nearly every sentence earns its place: limits, inputs, the PUT example, the follow-up listing, and the early-exit note. It is a touch run-on at the start, but the operational sequence is well ordered.

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?

No output schema or annotations exist, so the description must explain the return value and it does (a signed URL plus headers to use). It also covers the necessary follow-up step of listing the file in artifact.files. Complete for the core workflow, though edge-case behavior (expiry, limit errors) is left implicit.

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 both params (sha256, bytes) are already fully documented in the schema. The description restates 'sha256 (hex) and size in bytes' but adds no syntax or format detail beyond what the schema provides, 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?

The title and description state a specific verb+resource: obtaining a signed upload URL for an artifact file, with the exact size ceilings (50 MB/file, 500 MB/day). This is clearly distinguishable from retrieval siblings like get_artifact, and the two-step upload-then-list workflow is unambiguous.

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?

Explicitly scopes usage with 'For data or code that does not fit in an artifact's `code`' and adds the conditional 'If already_stored is true, skip the upload.' This gives clear when-to-use context, though it doesn't name a sibling alternative or state when-not beyond the early-exit flag.

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