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

With no annotations, the description carries the full burden and does disclose non-obvious behavior: is_custom defaults to true (registry image), the image reference format differs per mode, exactly one port must serve traffic, volumes persist data at container_path, and env_vars function defaults to TEXT. It stops short of stating permissions, idempotency, or what happens on a name collision, so it is strong but not complete.

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?

Purpose is correctly front-loaded, but the body is a dense run-on paragraph that jumbles prerequisites and per-field semantics together. It also near-verbatim repeats the schema's own image description ('repo:tag' vs fully-qualified public image), which spends words without adding new value.

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 moderately complex nested tool with no annotations and no output schema, the description covers the registration workflow, image sourcing modes, port/volume/env_vars semantics well enough to call it correctly. Missing only the return value and collision/permission behavior.

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?

Top-level schema descriptions are absent (reported coverage 0%), but the description compensates well by explaining the image reference format for both is_custom modes, the single-traffic-port constraint, container_path volume semantics, and the env_vars TEXT default. It does not explain the top-level 'name' or 'description' fields, but those are largely self-evident.

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+resource: 'Register a custom application definition from the user's own Docker images', and explicitly positions it upstream of the sibling create_app ('so it can be deployed with create_app'). An agent can distinguish this registration step from deployment without opening either 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?

Gives an explicit ordered workflow and prerequisite chain: push images first via get_registry_credentials, tag/push as <registry>/<app-name>:<tag>, then verify with list_custom_images. It names the downstream alternative (create_app) and the verification sibling (list_custom_images), leaving nothing to inference.

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