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

The readOnlyHint annotation already establishes that this is a safe read operation. The description adds useful behavioral context by naming the underlying API endpoint and specifying the returned shape, though it does not mention pagination, permissions, or error behavior.

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 description is compact and front-loaded, immediately stating the resource being listed and then adding useful endpoint and return-shape details. Every sentence contributes relevant information without waste.

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 simple one-parameter read-only tool with full schema description coverage and a clear readOnlyHint, the description is complete enough. It compensates for the lack of an output schema by describing the return structure.

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 has 100% description coverage and fully documents the single app parameter. The tool description does not add semantics beyond that, which is acceptable given the high schema coverage but not exceptional.

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: listing an app's container formation, including process types, amounts, and sizes. It clarifies that this is the current scaling, but it does not explicitly differentiate itself from sibling tools such as scalingo_scale_app.

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?

Usage is implied by describing the tool as listing the current container formation/scaling, but there is no explicit guidance on when to use it versus alternatives like scalingo_scale_app or scalingo_get_app_stats. It provides enough context for an agent to infer it is an inspection tool, but not explicit routing guidance.

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