get_image

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

With no annotations, the description carries the full burden and largely delivers: it discloses silent overwrite of existing files, mode preservation, 0600 for new files, streaming (never inlined), and that temp files persist after return. It stops short of error behavior (e.g., missing image) and authentication requirements, keeping it out of the top band.

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?

Front-loaded with the core action, then organized into short paragraphs covering disk behavior, temp-file default, and content-type reporting. Every sentence is informative, though the closing note about the response media type and the restated tilde-expansion edge toward redundancy with the schema/output schema.

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 two-parameter read/download tool with a high-coverage schema and an existing output schema, the description covers everything an agent needs: where the file lands, what happens to existing files, permissions, and the lifecycle of temp files. Return-value explanation is optional here and its presence is harmless.

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 the baseline is 3, and the description genuinely exceeds it by explaining the overwrite/mode semantics tied to output_path and restating that temp files persist for the caller to use or delete. The tilde-expansion and relative-path resolution it restates are already in the schema, so it is additive rather than purely new.

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 opening sentence gives a specific verb and resource ('Download an image to a file, written to disk') and immediately clarifies the streaming-to-disk model. No sibling tool in the list downloads images (upload_image is the inverse), so the agent can identify the correct tool without ambiguity.

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?

There is no explicit guidance on when to choose get_image versus alternatives, and no exclusions or prerequisites. Usage is only implied by the detailed discussion of the omitted-output_path path and temp-file workflow, which tells the agent how it will behave rather than when to reach for it.

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