Read an app file

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

Beyond the readOnlyHint annotation, the description discloses the full windowing contract: offset/length select the window, data_base64 carries exactly that window, next_offset continues, and sha256 hashes the whole file so reassembly is verifiable. This is substantial operational context that annotations and schema alone do not provide.

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 compact and front-loaded with the core action. Every sentence contributes useful information: window selection, continuation semantics, and reassembly/integrity checking, with no filler or repetition of schema details.

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 windowed file reader, the description covers selection, continuation, reassembly, and integrity checking. With an output schema present, this is sufficient for an agent to call the tool correctly and handle multi-window reads without additional inference.

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?

The schema already documents path, length, and offset, and the description reinforces their interaction: offset and length select the byte window, and next_offset continues reading. It adds useful meaning about reassembly and whole-file sha256 verification, though the app parameter remains undocumented.

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 opens with a clear, specific action: 'Read one file an app has stored' and identifies the resource as an app-stored file with windowed byte access. It is unambiguous about what the tool does, though it does not explicitly contrast itself with sibling tools like get_app or file_list.

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 intended use is implied: use this when you need to read the contents of one of an app's stored files, especially when windowed reads are needed. It references the same window grammar as get_app, but it does not explicitly state when to prefer file_read over alternatives 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.