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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds the underlying endpoint (GET /v1/apps/{app}) and the envelope shape ({ app }), which is genuine extra context, but says nothing about error behavior for missing apps or rate limits.

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 clauses, zero filler, with the core purpose and returned fields front-loaded before the endpoint and return shape. Every sentence earns its place.

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?

There is no output schema, and the description compensates by naming the returned fields and the { app } envelope, which is adequate for a single-read tool. It stops short of describing the field structure or failure modes, keeping it just shy of fully complete.

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% and the sole parameter already documents that app accepts a name or an app id with an example. The description adds nothing about parameter semantics beyond the schema, 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?

The description uses a specific verb and resource ('Fetch a single app's details') and enumerates the returned fields (region, stack, status, URLs, flags), which clearly separates it from list operations. It doesn't name a sibling such as scalingo_list_apps as the alternative, but the singular scope makes the distinction inferable.

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 only implied: the agent can infer 'call this when you need details for one specific app', but the description never states when to prefer it over scalingo_list_apps, scalingo_get_app_stats, or scalingo_get_app_logs. No prerequisites or exclusions are given.

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