list_variablesList an app's environment variables. WARNING: this exposes secret VALUES (API keys, database URLs, etc.). Scalingo API: GET /v1/apps/{app}/variables. Returns { variables: [{ id, name, value }] }.
| Name | Required | Description | Default |
|---|---|---|---|
| app | Yes | The app name (e.g. my-production-app) or app id (app-…). |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnlyHint annotation, the description warns that the tool exposes secret values (API keys, database URLs), which is critical behavioral context. It also specifies the API endpoint and response format.
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 three short sentences covering purpose, a security warning, and API details with no extraneous text. Every sentence adds 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 simple list tool with one parameter and no output schema, the description provides the return structure and a security warning. It lacks information about pagination or limits but is sufficient for basic usage.
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 already covers 100% of parameter descriptions, including that 'app' can be a name or ID. The description adds no additional meaning beyond what the schema provides.
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 clearly states 'List an app's environment variables' with a specific verb and resource. It distinguishes from sibling tools like set_variables and other list tools by focusing on variables and their values.
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 description does not provide guidance on when to use this tool versus alternatives like set_variables or other list tools. There is no explicit 'when to use' or 'when not to use' context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct resource or action: get_app vs get_app_logs vs get_app_stats are clearly different; list_addon_providers vs list_addons differentiate available vs provisioned. Mutation tools (restart, scale, trigger_deployment, set_variables) are unique. The fallback scalingo_request is a separate generic GET. No confusion between tools.
All tools use snake_case with a verb_noun pattern (get_, list_, restart_, scale_, trigger_, set_). The only exception is 'scalingo_request' which breaks the pattern, but it is clearly documented as a power-user escape hatch. Overall very consistent.
21 tools is well-scoped for a PaaS platform covering core resources like apps, deployments, addons, domains, env variables, and collaborators. It covers the essential operations without being bloated; each tool serves a clear purpose.
The toolset is heavily read-oriented; mutations are limited to restart, scale, set_variables, and trigger_deployment. Missing CRUD for major resources: no create/delete app, add/remove collaborators, add/remove domains, provision/delete addons, or update app settings. Agents will face dead ends when needing to perform writes beyond the few covered.