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

Annotations already declare readOnlyHint=true, and the description adds value beyond that: it names the backing endpoint (GET /v1/apps), scopes results to the current region, and discloses the return envelope { apps: [...] }. It does not mention result limits or pagination behavior, which is the only meaningful gap for a list tool.

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 sentences with zero filler, and the most important fact (what it lists and the access scope) is front-loaded before the endpoint and return-shape details.

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 parameterless read-only list tool this covers purpose, scope, and return shape adequately, and no output schema means the description's envelope hint matters. It stops short of explaining how the 'current region' is determined, which could matter given a scalingo_list_regions sibling exists.

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 zero parameters, so there is nothing to disambiguate; baseline 4 applies. Crediting the region scoping note, which tells the agent filtering happens via ambient context rather than an input.

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 ('List all Scalingo apps') plus a scope qualifier ('you can access in the current region') and the underlying endpoint. It implicitly contrasts with the singular scalingo_get_app, though it never names that sibling explicitly.

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?

The phrase 'apps you can access in the current region' implies this is the discovery step before calling get_app or other per-app tools, but no explicit when-to-use, when-not-to-use, or named alternative is given.

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