What is rails-ai-bridge rails-mcp-tools.instructions.md?

A set of instructions for an AI coding agent working on a Ruby on Rails application, with access to live project-inspection tools through MCP, a protocol for connecting assistants to tools.

Use it to inspect Rails schemas, models, routes, and controllers, then make changes while marking unverified assumptions and checking the results again.

It reduces guesses about database columns, routes, models, controllers, and project conventions by requiring the agent to check the application before making changes.

rails-ai-bridge rails-mcp-tools.instruc — Instructions file by igmarin

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo

git clone --depth 1 https://github.com/igmarin/rails-ai-bridge

Made for: GitHub Copilot.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/igmarin/rails-ai-bridge/rails-mcp-tools/github.svg)](https://agentmods.dev/instructions/igmarin/rails-ai-bridge/rails-mcp-tools)

Your own site

<a href="https://agentmods.dev/instructions/igmarin/rails-ai-bridge/rails-mcp-tools"><img src="https://agentmods.dev/badge/instructions/igmarin/rails-ai-bridge/rails-mcp-tools/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/igmarin/rails-ai-bridge/rails-mcp-tools"><img src="https://agentmods.dev/badge/instructions/igmarin/rails-ai-bridge/rails-mcp-tools.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 519 This file is loaded in full into every session.

When invoked 519 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00519	$0.00519
Opus 5.5	$0.00208	$0.00208
Sonnet 5.5	$0.00104	$0.00104
Haiku 4.5	$0.00052	$0.00052

Measured 1mo ago against content hash dda10ad674ec, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

rails-ai-bridge rails-mcp-tools.instructions.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

examples/demo_app/.github/instructions/rails-mcp-tools.instructions.md · 50 lines

What it actually says

MCP Tool Reference

This project has MCP tools for live introspection. Start with detail:"summary", then drill into specifics.

Anti-hallucination rules

Verify before you write (column, association, route, helper, gem).
Mark assumptions with [ASSUMPTION]. Silent guesses are forbidden.
This app is not average Rails. Query conventions and gems before scaffolding.
Check the inheritance chain (filters, concerns, STI) before editing a controller or model.
Empty tool output is information, not permission to invent.
Re-query after writes. Stale tool output lies.

Detail levels (schema, routes, models, controllers)

summary — names + counts (default limit: 50)
standard — names + key details (default limit: 15, this is the default)
full — everything including indexes, FKs (default limit: 5)

rails_get_schema

Params: table, detail, limit, offset, format

rails_get_schema(detail:"summary") — all tables with column counts
rails_get_schema(table:"users") — full detail for one table
rails_get_schema(detail:"summary", limit:20, offset:40) — paginate

rails_get_model_details

Params: model, detail

rails_get_model_details(detail:"summary") — list all model names
rails_get_model_details(model:"User") — full associations, validations, scopes

rails_get_routes

Params: controller, detail, limit, offset

rails_get_routes(detail:"summary") — route counts per controller
rails_get_routes(controller:"users") — routes for one controller

rails_get_controllers

Params: controller, detail

rails_get_controllers(detail:"summary") — names + action counts
rails_get_controllers(controller:"UsersController") — actions, filters, params

Other tools

rails_get_config — cache store, session, timezone, middleware
rails_get_test_info — test framework, factories/fixtures, CI config
rails_get_gems — notable gems categorized by function
rails_get_conventions — architecture patterns, directory structure
rails_search_code(pattern:"regex", file_type:"rb", max_results:20) — codebase search

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

1mo ago First seen · 50 lines · 519 tokens per session scan A dda10ad674ec

Subscribe to this mod's changes

rails-ai-bridge rails-mcp-tools.instructions.md is an instructions file published in the GitHub repository igmarin/rails-ai-bridge (16 stars, last pushed yesterday), licensed MIT. It adds 519 tokens to every session, about $0.0021 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-15.

Backend and APIs Building agents rails-ai rails-ai-assisted-development

vscode buildNext.instructions.md

Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).

microsoft/vscode · 9,649 tokens

rails-ai-bridge rails-mcp-tools.instructions.md