Upload a local image

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

Beyond the annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false), the description discloses that each call creates a new CDN object, the URL is public and undeletable, and nothing on the filesystem is modified. It also warns against uploading private content. This is rich, annotation-complementing behavioral detail.

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?

Every sentence earns its place: main action, usage guideline, behavioral warnings, and format constraints. The description is compact yet comprehensive, front-loaded with the primary purpose and followed by increasingly specific caveats.

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?

With only one parameter and no output schema, the description covers all essential context: return value (public URL), idempotency behavior, filesystem side effects (none), access restrictions (local only, API key), and format support. Nothing important is left unstated.

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?

Although the schema already fully documents 'file_path' with an example, the description adds semantics: absolute path required, accepted formats (JPEG, PNG, WebP, GIF), and that type is inferred from extension. This goes beyond the schema to make parameter usage foolproof.

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+outcome: 'Upload an image file from the local filesystem to the Misar.Blog CDN and return its public URL.' It also distinguishes the tool from its sibling 'generate_cover_image' by explicitly naming it, making the purpose unmistakable.

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?

Provides explicit when-to-use guidance: 'Use it for images the user already has on disk; use generate_cover_image when the image does not exist yet.' It additionally covers environmental constraints (local stdio only) and prerequisites (API key), leaving no ambiguity about when this tool is appropriate.

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