Save base64-encoded bytes to a specified device file, with a decoded size limit of about 4MB, enabling local file creation or transfer.
Writes base64-encoded bytes to a file on the device (max ~4MB decoded).
| Name | Required | Description | Default |
|---|---|---|---|
| path | Yes | Absolute file path. | |
| data_b64 | Yes | Base64-encoded content. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does disclose two real constraints: the base64 input format and a ~4MB decoded size limit. It says nothing about overwrite vs. append behavior, required permissions, where the file lands, or what happens on failure — significant gaps for a mutating 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?
A single tight sentence with no filler, and the encoding plus size constraint are front-loaded. Efficient, though it is arguably too terse for a write operation.
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?
Parameters are fully covered by the schema and there is no output schema to explain, so the core is adequate. However, for a mutation tool with zero annotations, the missing overwrite/permission/error semantics leave the definition only minimally sufficient.
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 both parameters are documented in the schema (absolute path, base64 content). The description's encoding mention reinforces data_b64 but adds no format or boundary detail beyond the schema, so 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?
States a specific verb and resource ('writes ... bytes to a file on the device') plus the exact encoding contract (base64-encoded). It is distinguishable from read_file, delete_file and list_files by the verb, though it never names those siblings 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?
Usage is implied by the name and the encoding requirement, but there is no explicit when-to-use guidance, no prerequisites, and no statement about how this differs from any alternative. An agent can infer the purpose but gets no routing help.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.