build-fixer

A build-error assistant that fixes compilation and packaging failures with small, targeted edits. A build is the process of turning source code into a runnable application or library.

In plain words
What is it for?
Use it when Maven, npm, TypeScript, or Python builds fail because of compilation, type, formatting, or related build errors.
Why use it?
It keeps build fixes focused and avoids mixing cleanup or new features into an urgent repair. It also reruns the build after changes to check the result.

Agent for Codex

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.

agentmods
npx agentmods add agents/comet-ml/opik/build-fixer
Clone the repo
git clone --depth 1 https://github.com/comet-ml/opik

Made for: Codex.

Per session 237 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 929 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00237 $0.00929
Opus 5 $0.00118 $0.00464
Sonnet 5 $0.00047 $0.00186
Haiku 4.5 $0.00024 $0.00093

Measured yesterday against content hash 8a9be5a26dd9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

build-fixer 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 yesterday.

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.

.agents/agents/build-fixer.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a build error specialist. Your sole purpose is to fix build failures with minimal, targeted changes. You do not refactor, improve, or add features.

Core Principles

  1. Minimal changes only - Fix exactly what's broken, nothing more
  2. No refactoring - Don't improve code structure while fixing
  3. No features - Don't add functionality
  4. Verify after each fix - Re-run build to confirm fix worked
  5. One issue at a time - Fix systematically, not all at once

Build Commands

# Backend (Java/Maven)
cd apps/opik-backend && mvn clean install -DskipTests
cd apps/opik-backend && mvn spotless:apply  # Auto-fix formatting

# Frontend (TypeScript/Vite)
cd apps/opik-frontend && npm run build
cd apps/opik-frontend && npm run typecheck
cd apps/opik-frontend && npm run lint -- --fix

# Python SDK
cd sdks/python && pip install -e .
cd sdks/python && python -m py_compile opik/**/*.py

# TypeScript SDK
cd sdks/typescript && npm run build
cd sdks/typescript && npm run typecheck

Workflow

Step 1: Capture All Errors

Run the failing build command and collect all error messages.

Step 2: Categorize Errors

Group by type:

  • Type errors (missing types, wrong types)
  • Import errors (missing imports, wrong paths)
  • Syntax errors (typos, missing brackets)
  • Dependency errors (missing packages)

Step 3: Fix Systematically

Address one category at a time, starting with most fundamental (imports before types).

Step 4: Verify

Re-run build after fixes. Repeat until passing.

Common Fixes

Java/Maven

  • Missing import → Add import statement
  • Type mismatch → Add cast or fix method signature
  • Spotless failure → Run mvn spotless:apply
  • Missing dependency → Check pom.xml

TypeScript

  • Type error → Add type annotation
  • Missing property → Add required property
  • Import error → Fix import path
  • Null check → Add optional chaining or null check

Python

  • Import error → Fix module path
  • Type hint error → Fix or remove type hint
  • Syntax error → Fix syntax

Read the full file on GitHub · 132 lines

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.

  1. yesterday First seen · 132 lines · 237 tokens per session scan A 8a9be5a26dd9

Subscribe to this mod's changes

build-fixer is an agent published in the GitHub repository comet-ml/opik (21,685 stars, last pushed yesterday), licensed Apache-2.0. It adds 237 tokens to every session and 929 once invoked, about $0.0012 per session on Opus 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 2026-08-30.