open-mcp-apps

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Read an app file

file_read

Read-onlyIdempotent

Read a file an app stored as byte windows by offset and length, then reassemble decoded data and verify the whole file with sha256.

Instructions

Read one file an app has stored, as a WINDOW of its bytes: offset/length select it, data_base64 carries exactly that window, next_offset continues (same window grammar as get_app, and for the same reason). Reassemble by concatenating decoded windows; sha256 is the WHOLE file's hash, so reassembly is checkable.

Input Schema

TableJSON Schema

Name	Required	Description
`app`	Yes
`path`	Yes	the file's logical name
`length`	No	max bytes for this window (default fits the result budget)
`offset`	No	byte offset to read from (default 0)

Output Schema

TableJSON Schema

Name	Required	Description	Default
`app`	Yes
`eot`	No
`mime`	Yes
`path`	Yes
`size`	Yes
`total`	No
`offset`	No
`sha256`	Yes
`version`	Yes
`returned`	No
`data_base64`	No
`next_offset`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedv0.6.0Sep 5, 2026
- removedOutput schema / properties / next_offset / anyOf
```
Removed value: -[
-  {
-    "type": "number"
-  },
-  {
-    "type": "null"
-  }
-]
```
- addedOutput schema / properties / next_offset / type
```
Added value: +[
+  "number",
+  "null"
+]
```
First observedv0.5.7Aug 15, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds non-obvious behavior the annotations cannot convey: reads are windows rather than whole-file, the default length fits a result budget (i.e. results may be truncated), and sha256 covers the whole file so reassembly is verifiable.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single dense sentence with the core action front-loaded and the reassembly/verification contract at the end. Every clause earns its place, though the parenthetical asides make it slightly harder to parse than necessary.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be spelled out, yet the description still explains the window/next_offset/sha256 contract that an agent must understand to read a file correctly. Nothing needed to invoke or complete a chunked read is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 75% and the schema documents offset/length defaults, but the description adds meaning beyond it: it explains the relationship between offset/length and the returned window, and names the response fields (data_base64, next_offset) that drive continued reads. This goes beyond the schema's per-parameter text.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Read one file an app has stored') with clear scope ('one file', 'an app has stored'), which separates it from file_list, file_write and get_app. It even cross-references the sibling whose window grammar it reuses, so an agent can place it without opening other schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage through the windowing model (call with offset/length, follow next_offset until done), but never states when to choose this tool over alternatives such as file_list or get_app, nor any exclusions. Usage is inferable rather than explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.