anon_post_materials_resource_id_versions

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

Annotations already declare destructive=true, idempotent=false, openWorld=true, so the safety profile is covered. The description adds real context beyond that: the version number auto-increments and supersedes the current version, the required permission, and the automatic WebP thumbnail generation with explicit constraints (png/jpeg/webp/gif whitelist, ≤800px, ≤100KB). It does not say whether prior versions are retained or how upload failures surface, but the added side-effect detail is substantial.

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?

Four tight sentences, front-loaded with the action, then permission, then side effects, then the endpoint and the projectId note. The endpoint and projectId lines partly restate the schema path, but nothing is wasted enough to undermine the structure.

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?

For a mutation tool with no output schema, the description supplies the essential prerequisites (permission), side effects (auto-increment, current-version replacement, thumbnail derivation) and parameter disambiguation. It stops short of describing the response payload or error conditions, which is the main remaining gap.

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?

Top-level schema descriptions are absent (0% coverage), but the description resolves a genuine ambiguity: the path template contains {id} yet no projectId parameter is required, which it explains. Nested schema descriptions already document base64/filename/mimeType/note, so the description need not repeat them; together the parameter semantics are well covered.

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?

States a specific verb+resource: uploading a new version of a material resource, with the concrete endpoint and the 'becomes current version' semantics. It is clearly a versioning write, distinct from the sibling anon_post_materials (create material), though it never names that sibling to sharpen the contrast.

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 states the required permission (materials:manage) and clarifies that projectId must NOT be passed because the project derives from the API key — genuine routing guidance. But it never says when to use this endpoint versus creating a new material (anon_post_materials) or editing existing metadata (anon_patch_materials_resource_id); usage is only implied by the verb.

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