Write a file into a Docker sandbox, replacing any file with the same name; the target folder must already exist.
Upload a file into the sandbox's files (replaces one of the same name); its folder must exist HTTP PUT /sandboxes/{name}/files/content
| Name | Required | Description | Default |
|---|---|---|---|
| body | Yes | The file's content | |
| name | Yes | ||
| path | Yes | The file to write, e.g. /root/app/config.json |
Changes observed during successful MCP inspections.
v0.7.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It discloses the destructive overwrite behavior and the folder precondition, which is more than nothing, but omits auth/permission requirements, size limits, and whether missing folders cause an error versus being created.
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?
One front-loaded sentence with the key constraint (replacement) in parentheses, plus the HTTP endpoint. Every element earns its place; no filler.
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?
No output schema and no annotations, so the description must stand alone. It covers overwrite and folder existence but leaves callers guessing on error behavior, permissions, and content-size constraints for a mutation tool.
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 coverage is 67%; body and path are already documented in the schema (path with an example). The description adds the path/folder precondition and overwrite behavior but does not clarify the undocumented 'name' parameter.
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 ('Upload a file into the sandbox's files') and its effect on same-named files. It clearly distinguishes itself from read_sandbox_file, delete_sandbox_file, and list_sandbox_files by naming the write/upload action, though it doesn't explicitly call out those siblings.
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?
Gives a concrete precondition ('its folder must exist') and notes overwrite semantics, which is genuinely useful. However, it offers no explicit when-to-use guidance versus alternatives, nor does it say 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.