diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b21f1b2..3d424bb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,9 +2,9 @@ name: CI
 
 on:
   push:
-    branches: [main, master]
+    branches: [main]
   pull_request:
-    branches: [main, master]
+    branches: [main]
 
 permissions:
   contents: read
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 5f14867..ddfa717 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -2,9 +2,9 @@ name: CodeQL
 
 on:
   push:
-    branches: [main, master]
+    branches: [main]
   pull_request:
-    branches: [main, master]
+    branches: [main]
   schedule:
     - cron: '0 3 * * 1'
 
diff --git a/README.md b/README.md
index 0c7bf84..1d37eb0 100644
--- a/README.md
+++ b/README.md
@@ -3,9 +3,9 @@
 
 [![PyPI](https://img.shields.io/pypi/v/instinct-mcp?color=%2334D058&label=pypi)](https://pypi.org/project/instinct-mcp/)
 [![Python](https://img.shields.io/pypi/pyversions/instinct-mcp)](https://pypi.org/project/instinct-mcp/)
-[![CI](https://github.com/yakuphanycl/instinct/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/yakuphanycl/instinct/actions/workflows/ci.yml)
-[![CodeQL](https://github.com/yakuphanycl/instinct/actions/workflows/codeql.yml/badge.svg?branch=master)](https://github.com/yakuphanycl/instinct/actions/workflows/codeql.yml)
-[![License](https://img.shields.io/github/license/yakuphanycl/instinct)](https://github.com/yakuphanycl/instinct/blob/master/LICENSE)
+[![CI](https://github.com/yakuphanycl/instinct/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/yakuphanycl/instinct/actions/workflows/ci.yml)
+[![CodeQL](https://github.com/yakuphanycl/instinct/actions/workflows/codeql.yml/badge.svg?branch=main)](https://github.com/yakuphanycl/instinct/actions/workflows/codeql.yml)
+[![License](https://img.shields.io/github/license/yakuphanycl/instinct)](https://github.com/yakuphanycl/instinct/blob/main/LICENSE)
 [![MCP](https://img.shields.io/badge/MCP-compatible-blue)](https://modelcontextprotocol.io)
 
 Self-learning memory for AI coding agents: record repeated patterns, score them by confidence, and surface mature guidance back through MCP.
diff --git a/SECURITY.md b/SECURITY.md
index 17e14ff..29d007d 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -2,7 +2,7 @@
 
 ## Supported Versions
 
-Security fixes are applied to the latest release on `master`.
+Security fixes are applied to the latest release on `main`.
 
 ## Reporting a Vulnerability
 
diff --git a/pyproject.toml b/pyproject.toml
index 9cd75a0..d4fb675 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,7 +30,7 @@ dependencies = [
 Homepage = "https://github.com/yakuphanycl/instinct"
 Repository = "https://github.com/yakuphanycl/instinct"
 Issues = "https://github.com/yakuphanycl/instinct/issues"
-Changelog = "https://github.com/yakuphanycl/instinct/blob/master/CHANGELOG.md"
+Changelog = "https://github.com/yakuphanycl/instinct/blob/main/CHANGELOG.md"
 
 [project.scripts]
 instinct = "instinct.cli:main"