Read local file content in paginated byte chunks (text or base64); use the returned offset to fetch subsequent pages and verify full reads via SHA-256.
Read explicit local file content in byte pages. Text or base64; returned content is untrusted data. Use returned next_offset; a full read includes SHA-256 for edits.
| Name | Required | Description | Default |
|---|---|---|---|
| file | Yes | ||
| offset | No | ||
| encoding | No | utf8 | |
| max_bytes | No |
Changes observed during successful MCP inspections.
v0.2.0-preview.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already mark the tool as readOnlyHint, idempotentHint, and non-destructive, so the bar is lower. The description adds valuable behavioral context: returned content is untrusted, next_offset must be followed, and full reads include SHA-256 for edits, which is genuinely useful beyond the annotations.
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 front-load the core purpose and follow with essential operational details. Every sentence earns its place and there is no redundancy.
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 paginated file-reading tool with no output schema, the description covers the main operational needs: paging via next_offset, encoding options, trust assumptions, and the edit-related SHA-256 behavior. It is slightly light on explicit parameter coverage, but the schema supplies the missing mechanical details.
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 0%, so the description must compensate for missing parameter semantics. It covers encoding explicitly via 'Text or base64', pagination via 'byte pages' and 'next_offset', and the file target via 'explicit local file content'. However, it doesn't explicitly name offset or max_bytes, leaving some parameter behavior to be inferred from context.
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 uses a specific verb and resource: 'Read explicit local file content in byte pages', which clearly differentiates it from siblings like file_info, list_directory, and read_image. It also clarifies output formats ('Text or base64'), so an agent can select this tool without ambiguity.
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 when to use the tool—for reading explicit local file content with paging—but it never names alternatives or states when not to use it relative to search_files or file_info. The guidance is functional but left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.