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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false; the description reinforces this with "opens nothing by itself", so an agent knows no state changes occur. It also explains why the browser-tool handoff is required (Midjourney has no public API), which is genuine behavioral context not encoded in the annotations. It could go further by describing the shape of the returned instructions or whether they are account-specific.

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 core message is front-loaded, but the middle sentence is a run-on that bundles the return value, the no-side-effects guarantee, and the follow-on action, which muddles the reading order. The closing "Midjourney's official API: Midjourney has no public API (checked 5 Nov 2026)" is awkwardly phrased and includes a verification date that adds little for an agent.

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 zero-parameter, read-only guide tool with no output schema, the description supplies what matters: what it returns (step-by-step screens/buttons/fields), that it takes no side effects, and what to do next with the cotlet_browser_* tools. Only the format of the returned instructions and any account prerequisites remain unspecified.

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?

The input schema is empty (0 parameters, 100% coverage), so there are no parameter semantics to explain; the baseline for zero-parameter tools applies. The description correctly signals that the call needs no arguments and that the image context comes from elsewhere (the user's Midjourney account).

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 ("Animate image in the user's own Midjourney account") and immediately clarifies that the tool returns step-by-step instructions rather than performing the animation itself, which resolves the mismatch between the name and the read-only payload. It does not, however, distinguish itself from siblings such as midjourney_extend_video or midjourney_create_images, so an agent still has to infer which Midjourney tool applies to an animating task.

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?

Gives an explicit follow-on workflow: it returns screens/buttons/fields, then the agent should act with the cotlet_browser_* tools in the user's Midjourney Cloud Browser. That is real when-and-how guidance rather than a restatement of the name. It stops short of naming alternatives or exclusions (e.g., when to use this instead of extend_video or create_images).

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