Create or update a file in an app. Parent directories are created automatically. Maximum content size: 1MB. The app will auto-restart when files change.
| Name | Required | Description | Default |
|---|---|---|---|
| app | Yes | App ID (UUID) or subdomain | |
| path | Yes | File path to write (e.g. "index.js", "src/app.ts") | |
| content | Yes | File content to write |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the full burden of disclosing behavior. It covers three important side effects: automatic creation of parent directories, the 1MB content cap, and automatic app restart on file changes. It does not mention overwrite semantics or permission requirements, but the main effects are well documented.
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 four concise sentences, each providing essential information. It is front-loaded with the core action and contains no redundant or filler wording.
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 3-parameter write tool, the description covers the main action, path behavior, size limit, and restart side effect. It does not describe return values or error cases, but that is not critical given the straightforward nature of the operation and the absence of an output schema.
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?
All three parameters are already described in the schema, so the baseline is 3. The description adds value by linking the path parameter to automatic parent directory creation and the content parameter to the 1MB limit, which goes beyond simple schema definitions.
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 'Create or update a file in an app' with a specific verb and resource. It distinguishes itself from sibling tools like read_file, delete_file, and rename_file by focusing on writing file content.
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 implies usage for writing or updating file contents, and adds practical constraints like automatic directory creation and the 1MB size limit. However, it does not explicitly mention when to use this tool over upload_file or when not to use it.
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.
Most tools have clearly distinct purposes, but a few pairs could be confused: get_app vs. get_app_status both report on app state, and update_app vs. set_node_version both modify runtime configuration. Descriptions are detailed enough to mitigate most ambiguity, but the overlap is notable.
Tool names largely follow a consistent verb_noun snake_case pattern (e.g., list_apps, create_app, delete_file). Minor deviations include the bare verb 'login' and the noun-first 'git_info', which break the pattern slightly but are still understandable.
At 37 tools, the set is on the heavy side, well above the typical 3-15 range. However, the server covers a broad PaaS domain (auth, app lifecycle, file management, packages, versions, git, metrics), and each tool addresses a distinct operation. It feels over-engineered in places but not gratuitously so.
The tool surface is impressively complete for a deployment platform: authentication, app CRUD, start/stop/restart, file operations (read/write/delete/rename/search/upload), package management, version snapshots and restore, git remote and push/pull, logs, metrics, and configuration. No critical dead-ends are apparent.
