Save one Midjourney asset by URL

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, so the description only needs to add nuance. It adds the important auth/session limitation and clarifies that this is a direct download rather than a job-id fetch. It does not contradict the annotations.

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?

Three short, purposeful sentences with the core action front-loaded. There is no filler or repetition of schema field descriptions, and each sentence adds either selection context or a behavioral constraint.

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 tool with 3 parameters, full schema coverage, and no output schema, this is complete enough to invoke correctly. It covers purpose, use case, alternative path, auth limitation, and parameter defaults. The title and verb already communicate the save-to-disk side effect.

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%, including the direct-URL meaning, the out_dir default, and filename derivation from the URL. The description itself adds no parameter-level detail, but the schema already carries that burden, so the baseline 3 applies.

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?

Opens with a specific verb and resource: 'Download a single Midjourney asset by its direct URL.' The qualifiers 'single' and 'direct URL' clearly distinguish it from the job-id-based download path of a sibling like download_job. It is not a tautology or a vague restatement of the title.

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?

Explicitly states when to use it: when image URLs are already in hand from list_jobs, explore_feed, or a moodboard, and going back through a job id would be a detour. It also gives an exclusion: only useful for URLs the signed-in browser session can reach. This gives the agent concrete selection criteria versus alternatives.

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