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

With no annotations, the description carries the full behavioral burden. It discloses key traits: the password is the caller's own API token, restricted to read_write keys, compatible with docker/podman/skopeo login and CI, and image paths are automatically scoped to the account. Missing details like token expiry or rate limits keep it from a 5.

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 sentences, front-loaded with the primary action, then authentication constraints, then downstream usage. Every clause adds actionable value with no filler or repetition.

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 tool with no output schema and no annotations, the description supplies credential nature, compatibility, scoping behavior, and the create_custom_app handoff. It omits the exact shape of returned instructions and token expiry details, but is largely complete for an agent to call it 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?

The tool takes 0 parameters, so there is no parameter semantics to document; baseline 4 is appropriate. The description adds no meaningful parameter information because none exists.

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 states a specific verb and resource ('Get Docker registry login credentials and step-by-step instructions for pushing custom images') and clearly distinguishes itself from siblings like list_custom_images or create_custom_app. An agent can identify the tool's output without opening any schema.

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?

It explains the authentication caveat ('read_write keys only'), compatibility targets ('docker/podman/skopeo login and in CI'), and the downstream workflow with create_custom_app ('reference them in create_custom_app as <app-name>:<tag> with is_custom true'). It lacks an explicit when-not-to-use statement but provides strong contextual routing.

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