---
title: "Agents on large codebases"
url: https://www.grahambrooks.com/series/agents-on-large-codebases/
---

# Agents on large codebases

- [When an agent can already write the file, what is an MCP server for?](https://www.grahambrooks.com/post/what-is-an-mcp-server-for/index.md) (2026-10-04): If an agent can already write your tool's file format, an MCP server has to give it something the file can't: live discovery, validation against the real system, a preview of the result, and a save with rules. Teleplot's endpoint was built only because it passed that gate, and it passed more narrowly than I first thought. Most MCP servers should fail it and be a file format plus a linter.
- [Making a Code Graph Admit What It Doesn't Know (symgraph)](https://www.grahambrooks.com/post/symgraph-admitting-what-it-does-not-know/index.md) (2026-09-22): A code-intelligence index answered every question it was asked. Sixteen percent of its call edges pointed at things that cannot be called, its truncated lists said nothing about being truncated, and one of its tools had never worked at all. The month's work was almost entirely about replacing confident answers with calibrated ones.
- [The Agentic Inner Loop: Sensors, Substrate, and Skills for Polyglot Development](https://www.grahambrooks.com/post/inner-loop-agentic-development/index.md) (2026-05-23): What the developer inner loop becomes when a coding agent is doing most of the iteration — and the substrate, sensors, codemods, and skills you need to build for it.
- [Code Review After the Pull Request](https://www.grahambrooks.com/post/code-review-after-the-pull-request/index.md) (2026-04-26): The pull request was built for a world where humans wrote most of the code. We don’t live there anymore. The pull request as a unit of review is a recent invention. GitHub shipped it in 2008. Before that, code…
- [A Code Knowledge Graph for Review, Not Generation](https://www.grahambrooks.com/post/code-knowledge-graph-for-review/index.md) (2026-04-26): The same graph that helps an agent write code can help a reviewer trust it. Almost nobody is using it that way. Every AI coding tool I’ve looked at in the last eighteen months — including codemap now called symgraph—…
- [Building a Code Knowledge Graph for AI Agents](https://www.grahambrooks.com/post/building-a-code-knowledge-graph-for-ai-agents/index.md) (2026-02-15): Building a Code Knowledge Graph for AI Agents How I rebuilt codegraph in Rust to give AI coding assistants a semantic map of your codebase There’s a fundamental tension at the heart of agentic coding today. AI models are remarkably…