Feature/firebender support #249

barisatalay · 2025-09-20T14:13:13Z

This pull request adds support for the Firebender agent to the project, allowing Ruler to generate and manage configuration for Firebender via a new adapter. It updates documentation, the agent registry, and includes comprehensive unit tests to ensure correct behavior for rule processing, MCP server configuration, and file operations.

Firebender: https://firebender.com/
Docs: https://docs.firebender.com/context/configurations

Firebender agent support:

Introduced a new FirebenderAgent class in src/agents/FirebenderAgent.ts that implements the IAgent interface. This agent generates and updates firebender.json with rules and MCP server configuration, supports merging or overwriting MCP servers, and handles both plain text and file-based rules.
Registered the new agent in the agent index (src/agents/index.ts) by importing and adding FirebenderAgent to the allAgents array. [1] [2]

Documentation updates:

Updated README.md to document Firebender as a supported agent, including its output file, usage in --agents, and example commands for applying rules to Firebender. [1] [2] [3] [4]

Testing and robustness:

Added a comprehensive test suite for FirebenderAgent in tests/unit/agents/FirebenderAgent.test.ts, covering rule creation, merging, deduplication, MCP configuration strategies, file operations, and error handling.

Type safety improvements:

Refactored MCP propagation code for type safety by introducing an OpenHandsConfig interface in src/mcp/propagateOpenHandsMcp.ts and using it for config parsing. [1] [2]

Implementation

Identifier: firebender
Output file: firebender.json (in project root)
MCP support: Enabled (in firebender.json)

Usage

Users can now target the Firebender agent specifically:

# Apply rules only to Warp
ruler apply --agents firebender

# Use with other agents
ruler apply --agents firebender,claude

The agent can also be configured in ruler.toml:

default_agents = ["firebender"]

# Firebender agent configuration
[agents.firebender]
enabled = true

[agents.firebender]
enabled = true

[agents.firebender.mcp]
enabled = true
merge_strategy = "overwrite"  # or "merge"

Introduces the FirebenderAgent implementation, updates agent registry, and documents Firebender usage in the README. Includes unit tests for FirebenderAgent and minor type fix in propagateOpenHandsMcp.

Introduces handling of MCP server configuration in FirebenderAgent, allowing merging or overwriting of MCP servers in firebender.json based on strategy. Updates support flags for MCP, adds related methods, and provides comprehensive unit tests for MCP configuration scenarios.

Introduced explicit TypeScript interfaces for Firebender and OpenHands configuration structures to improve type safety and code clarity. Updated method signatures and internal logic in FirebenderAgent and propagateOpenHandsMcp to use these new types.

intellectronica · 2025-09-20T14:17:49Z

@barisatalay why the change to propagateOpenHandsMcp.ts? Doesn't look relevant to this feature.

Copilot

Pull Request Overview

Adds Firebender agent support, enabling Ruler to generate and manage firebender.json, including rules and MCP server configuration. Key changes:

New FirebenderAgent with rule processing, MCP merge/overwrite strategies, and file operations (backups, custom paths).
Registration of FirebenderAgent and documentation updates to include it in CLI options and usage.
Type-safety refactor in propagateOpenHandsMcp via an OpenHandsConfig interface.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/agents/FirebenderAgent.ts	Implements FirebenderAgent: rules parsing, deduplication, MCP server merge/overwrite, backups, output path resolution.
tests/unit/agents/FirebenderAgent.test.ts	Unit tests covering rules (plain and file-based), deduplication, MCP strategies, backups, and malformed JSON handling.
src/agents/index.ts	Registers FirebenderAgent in the agent registry.
src/mcp/propagateOpenHandsMcp.ts	Introduces OpenHandsConfig and uses it for config parsing.
README.md	Documents Firebender agent, CLI usage, and availability in --agents and revert lists.

README.md

src/agents/FirebenderAgent.ts

intellectronica · 2025-09-20T14:21:15Z

@barisatalay also why so much new code in FirebenderAgent.ts‎? Surely you could inherit a lot of that from AbstractAgent, no? Or am I missing something?

intellectronica · 2025-09-20T14:23:13Z

@barisatalay also see the comments from Copilot, they are all valid (except for one that I resolved).

refactor: rollback propagateOpenHandsMcp development

barisatalay · 2025-09-20T14:48:21Z

@barisatalay why the change to propagateOpenHandsMcp.ts? Doesn't look relevant to this feature.

You’re right, that was my mistake — I rolled it back.

@barisatalay also see the comments from Copilot, they are all valid (except for one that I resolved).

Thanks for highlighting these, I’ll go ahead and fix them 👍

@barisatalay also why so much new code in FirebenderAgent.ts‎? Surely you could inherit a lot of that from AbstractAgent, no? Or am I missing something?

Actually "AbstractAgent" is really good but in "Firebender" rule definition and mcp definition system is a little more complicated than other tools.

For example: All definitions in one

{
  "rules": [
    "string rule",
    {
      "filePathMatches": "glob/pattern",
      "rules": ["rule1", "rule2"]
    }
  ],
  "ignore": [
    "glob/pattern1",
    "glob/pattern2"
  ],
  "mcpServers": {
    "serverName": {
      "command": "executable",
      "args": ["arg1", "arg2"],
      "env": {"KEY": "VALUE"}
    }
  },
  "mcpEnvFile": "path/to/env/file"
}

Thanks for pointing this out — there might be things I’ve overlooked, and your feedback is really valuable 🙏

Updated the Firebender configuration file path from `.firebender.json` to `firebender.json` in the documentation for accuracy.

Previously, object rules were deduplicated only by rulesPaths, causing valid distinct rules with different filePathMatches to be incorrectly removed. Now uses `filePathMatches::rulesPaths` composite key. Includes test case for the fix.

…adFile Use async I/O with ENOENT handling instead of existsSync/readFileSync for better consistency and non-blocking operations.

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

src/agents/FirebenderAgent.ts

README.md

Prevent malicious HTML comments from accessing files outside project directory via path traversal attacks.

Replace unsafe type assertion with type guard function Add isFirebenderRule() for safe FirebenderRule validation Addresses PR review feedback on type checking

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

src/agents/FirebenderAgent.ts

Co-authored-by: Copilot <[email protected]>

Copilot

Pull Request Overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

tests/unit/agents/FirebenderAgent.test.ts

src/agents/FirebenderAgent.ts

barisatalay added 3 commits September 20, 2025 01:10

Add Firebender agent support

1c7303f

Introduces the FirebenderAgent implementation, updates agent registry, and documents Firebender usage in the README. Includes unit tests for FirebenderAgent and minor type fix in propagateOpenHandsMcp.

chora: solve eslint problems

dbebe52

Introduced explicit TypeScript interfaces for Firebender and OpenHands configuration structures to improve type safety and code clarity. Updated method signatures and internal logic in FirebenderAgent and propagateOpenHandsMcp to use these new types.

intellectronica requested a review from Copilot September 20, 2025 14:17

Copilot AI reviewed Sep 20, 2025

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refactor: rollback propagateOpenHandsMcp development

88a4d02

refactor: rollback propagateOpenHandsMcp development

barisatalay added 3 commits September 20, 2025 17:49

fix: Firebender config file path in README

2fc4479

Updated the Firebender configuration file path from `.firebender.json` to `firebender.json` in the documentation for accuracy.

refactor(firebender): replace sync fs calls with async fs.promises.re…

8778d1f

…adFile Use async I/O with ENOENT handling instead of existsSync/readFileSync for better consistency and non-blocking operations.

barisatalay requested a review from Copilot September 20, 2025 20:04

Copilot AI reviewed Sep 20, 2025

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intellectronica reviewed Sep 20, 2025

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barisatalay added 2 commits September 20, 2025 23:22

fix: solve path traversal vulnerability in FirebenderAgent

c371f28

Prevent malicious HTML comments from accessing files outside project directory via path traversal attacks.

refactor: improve type safety in FirebenderAgent

8c29c97

Replace unsafe type assertion with type guard function Add isFirebenderRule() for safe FirebenderRule validation Addresses PR review feedback on type checking

barisatalay requested a review from Copilot September 20, 2025 20:34

Copilot AI reviewed Sep 20, 2025

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Update src/agents/FirebenderAgent.ts

dc9924c

Co-authored-by: Copilot <[email protected]>

barisatalay requested a review from Copilot September 20, 2025 20:36

Copilot AI reviewed Sep 20, 2025

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intellectronica merged commit f7eb4b1 into intellectronica:main Sep 20, 2025
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Feature/firebender support #249

Feature/firebender support #249

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Implementation

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intellectronica commented Sep 20, 2025

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intellectronica commented Sep 20, 2025

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barisatalay commented Sep 20, 2025 •

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