Work with local files¶

Reyn can read files from your project and answer questions about them — no special syntax required. Just describe what you want in plain language.

Before you start: one-time setup¶

File access goes through the filesystem MCP server. Add the following block to your reyn.yaml if it is not already there:

permissions:
  mcp.filesystem: allow   # skip the per-call prompt

mcp:
  servers:
    filesystem:
      type: stdio
      command: npx
      args: ["-y", "@modelcontextprotocol/server-filesystem", "."]

The . at the end of args sets the server's root to your current directory. Everything inside that directory tree is readable; paths outside it are not.

If you skip the permissions line, Reyn will prompt you to approve each read interactively. That works fine in the TUI; it will block in headless environments.

See How-to: Manage permissions for the full options.

Reference a single file¶

Write the file path naturally — Reyn understands both casual descriptions and exact paths:

> Summarise the README
> What does pyproject.toml declare as dependencies?
> Explain what src/reyn/runtime.py does

The skill resolves the path and reads the file before composing its answer. It tells you which file it actually read at the end of the response.

Reference multiple files¶

Name more than one file in a single request:

> Compare the approach in docs/concepts/workspace.md and docs/concepts/events.md
> What's different between src/reyn/models.py and src/reyn/op_runtime/registry.py?
> Read CHANGELOG.md and pyproject.toml and tell me what version we are on

Reyn reads up to five files per turn. If a request would need more, break it into follow-up turns.

Ask about a directory¶

Name a directory and Reyn picks the most relevant entry point — an __init__.py, index.md, README, or similar:

> What's in src/reyn/op_runtime/?
> Walk me through what's under docs/concepts/

It will not read every file in a large directory; it infers which file to start from. If it picks the wrong one, tell it which file you meant and it will re-read.

Common scenarios¶

Summarise documentation¶

> Summarise the philosophy section of docs/concepts/principles.md
> Give me a one-paragraph overview of docs/guide/for-users/index.md

Understand source code¶

> What does the `ContextFrame` class in src/reyn/models.py do?
> List the public functions in src/reyn/op_runtime/registry.py
> How does src/reyn/runtime.py start a skill run?

Check configuration¶

> What MCP servers are configured in reyn.yaml?
> Does this project have any pre-approved permissions?

Spot differences¶

> What changed between the two versions described in CHANGELOG.md?
> Compare the input schemas in these two artifact YAML files

What the skill cannot do¶

Write or modify files — read_local_files is read-only. If you need to edit a file, say so explicitly; the router will pick a different skill.
Read files outside the server root — if you configured the server with . as root, paths like /etc/passwd or ~/.ssh/config are outside scope and will return an error. The server enforces this boundary, not Reyn.
Read binary files — the underlying tool is read_text_file. Images, compiled artifacts, and other binaries are not supported.

Troubleshooting¶

"permission denied" on every read

Add mcp.filesystem: allow to the permissions: block in reyn.yaml (see setup above) or answer the interactive prompt with [y] during a TUI session.

"path outside project scope" error

The filesystem MCP server's root is set when you start it (the final argument in args). Paths must be relative to that root. Absolute paths and ../-escaping paths are rejected by the server.

Reyn reads the wrong file

Say which file you meant:

> Not that one — I meant src/reyn/op_runtime/registry.py

The skill will re-read the correct path.

No response, or "skill exited empty"

The filesystem server may not be running or may be misconfigured. Check that mcp.servers.filesystem is present in reyn.yaml and that npx is installed (npx --version).