view_region

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

With no annotations, the description carries the full burden. It does add real behavioral value: the server picks the best available resolution, and the response includes a crop-pixel-to-canvas-coordinate mapping. It omits safety profile (implicitly a read, but unstated), any auth/access constraints, how max_side interacts with the server-side resolution cap, and failure behavior.

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?

Two short sentences, front-loaded with the action and followed by return-value information. Nothing is wasted, though it is under-specified rather than maximally efficient.

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 explaining the return shape is optional, but the tool has 7 parameters at 0% schema coverage and zero annotations. The description should at minimum explain max_side's effect and where manifest_url/canvas_id come from; that gap makes it incomplete for an agent to invoke correctly.

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 0% for 7 parameters. The description clarifies that x/y/w/h are canvas coordinates, which is genuinely useful, but says nothing about manifest_url, canvas_id, or max_side (default 1568) — the parameter that most affects output size. It does not compensate for the coverage gap.

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 and resource ('Fetch a canvas region') with the coordinate space made explicit (canvas coordinates) and the resolution policy noted. It does not differentiate from the sibling describe_manifest, which is presumably the manifest/canvas-discovery step an agent needs first.

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?

No statement of when to call this versus describe_manifest, and no prerequisites are given — despite manifest_url and canvas_id almost certainly coming from a prior manifest inspection. Only the implicit hint that this tool handles resolution selection itself.

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