upload_images

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

With no annotations, the description fully discloses behavioral traits: it reads/downloads and re-uploads, processes up to 20 entries in parallel, converts non-jpeg/png/webp to JPEG, caches per site, and defaults to actual uploads (dry_run=false). It also explains dry_run semantics including local path existence checks. This goes far beyond what structured metadata would provide.

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 about 150 words across two paragraphs, but every sentence carries essential information. It front-loads the primary purpose, then adds usage guidance, technical constraints, and error/edge-case handling. No filler or repetition; the length is justified by the tool's complexity and lack of annotations.

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?

Despite having no output schema and no annotations, the description is complete. It explains the return format ('images' map), the default mutation behavior, caching benefits, batch/parallel processing, format conversion, dry_run preview, and file path restrictions. This is more than sufficient for an agent to decide when and how to invoke the tool.

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 description coverage is 100%, so the baseline is 3. The description adds operational meaning beyond the schema: parallel processing limit, format conversion behavior, dry_run defaults and preview details, and the stdio-only restriction for local paths. These extras justify above baseline, though the schema already documents the core parameter types and defaults.

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+resource: 'Convert external image URLs, data: URIs, or LOCAL FILE PATHS into site-hosted CDN URLs by reading/downloading each image and re-uploading it to the WebCake backend.' This clearly states the tool's function and differentiates it from sibling tools like read_image or search_images by emphasizing conversion to CDN URLs and the requirement for whitelisted domains.

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 explicitly states when to use the tool: 'Use this whenever the user supplies their OWN images...' and 'This is REQUIRED for any external image (incl. Pexels search results)...' It also provides a when-not constraint: local file paths are only permitted on stdio, not remote HTTP. However, it does not name alternative tools, so it stops short of fully explicit alternatives.

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