diff --git a/.agents/shared-module-guardrails.md b/.agents/shared-module-guardrails.md
new file mode 100644
index 00000000000..35aba7049ac
--- /dev/null
+++ b/.agents/shared-module-guardrails.md
@@ -0,0 +1,21 @@
+# Shared module guardrails
+
+These rules apply in directories whose `AGENTS.md` links here.
+
+- Leave these modules untouched by default. Implement product features in their own modules using existing
+  contracts. Do not implement product specific feature into shared modules.
+- Change a shared module only for a concrete goal in that module. Language Platform @DataDog/apm-lang-platform-java should lead such work.
+  Outside that team, keep changes tactical and specific to this module. Put them in a separate PR from broader
+  product work.
+- Before editing, tell the user the goal for the module and why an exception is needed. If that rationale is
+  unclear, leave the module untouched. Warn that Language Platform @DataDog/apm-lang-platform-java review is needed.
+- Under `# Motivation` in the PR, add `## Shared module change` apart from any product motivation. Explain
+  the goal for this module, why the work belongs here, affected consumers, and compatibility risks. When
+  prompted by product work, explain why product code and existing contracts cannot meet the need.
+- Check [CODEOWNERS](../.github/CODEOWNERS) for the current area owner. Put this GitHub alert at the very start
+  of the PR description, before `# What Does This Do`:
+
+  ```markdown
+  > [!IMPORTANT]
+  > Language Platform review is needed for this shared module change. Please involve @DataDog/apm-lang-platform-java.
+  ```
diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 09e44b790e1..78a1fc07cfc 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -19,6 +19,7 @@
 
 # Shared communication
 /communication/*.*                                                   @DataDog/apm-java
+/communication/*.md                                                  @DataDog/apm-lang-platform-java
 /communication/src/*/*/datadog/communication/*.*                     @DataDog/apm-java
 /communication/src/*/*/datadog/communication/ddagent/                @DataDog/apm-java
 /communication/src/*/*/datadog/communication/http/                   @DataDog/apm-java
@@ -29,6 +30,7 @@
 /communication/src/test/resources/                                   @DataDog/apm-java
 
 # Shared utility modules
+/utils/*.md               @DataDog/apm-lang-platform-java
 /utils/filesystem-utils/  @DataDog/apm-java
 /utils/logging-utils/     @DataDog/apm-java
 /utils/queue-utils/       @DataDog/apm-java
@@ -47,6 +49,7 @@
 /dd-java-agent/load-generator/         @DataDog/apm-java
 
 # Core tracing API
+/dd-trace-api/*.md                                    @DataDog/apm-lang-platform-java
 /dd-trace-api/src/*/*/datadog/trace/api/*.*           @DataDog/apm-java
 /dd-trace-api/**/config/CwsConfig*                    @DataDog/apm-java
 /dd-trace-api/**/config/GeneralConfig*                @DataDog/apm-java
@@ -58,6 +61,7 @@
 /dd-trace-api/src/*/*/datadog/trace/payloadtags/      @DataDog/apm-java
 
 # Core tracer
+/dd-trace-core/*.md                                          @DataDog/apm-lang-platform-java
 /dd-trace-core/src/test                                      @DataDog/apm-java
 /dd-trace-core/src/*/*/datadog/context/*.*                   @DataDog/apm-java
 /dd-trace-core/src/*/*/datadog/trace/api/naming/             @DataDog/apm-java
@@ -80,6 +84,7 @@
 /dd-trace-core/src/traceAgentTest/                           @DataDog/apm-java
 
 # Core internal API
+/internal-api/*.md                                     @DataDog/apm-lang-platform-java
 /internal-api/internal-api-9/                          @DataDog/apm-java
 /internal-api/src/test                                 @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/advice/            @DataDog/apm-java
diff --git a/communication/AGENTS.md b/communication/AGENTS.md
new file mode 100644
index 00000000000..1e3ffc7cecc
--- /dev/null
+++ b/communication/AGENTS.md
@@ -0,0 +1,5 @@
+# communication
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/communication/CLAUDE.md b/communication/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/communication/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/components/AGENTS.md b/components/AGENTS.md
new file mode 100644
index 00000000000..c0fae2fc8dc
--- /dev/null
+++ b/components/AGENTS.md
@@ -0,0 +1,5 @@
+# components
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/components/CLAUDE.md b/components/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/components/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-java-agent/agent-bootstrap/AGENTS.md b/dd-java-agent/agent-bootstrap/AGENTS.md
new file mode 100644
index 00000000000..90e1148e1e4
--- /dev/null
+++ b/dd-java-agent/agent-bootstrap/AGENTS.md
@@ -0,0 +1,5 @@
+# agent-bootstrap
+
+Module described in [ARCHITECTURE.md](../../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../../.agents/shared-module-guardrails.md).
diff --git a/dd-java-agent/agent-bootstrap/CLAUDE.md b/dd-java-agent/agent-bootstrap/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-java-agent/agent-bootstrap/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-java-agent/agent-installer/AGENTS.md b/dd-java-agent/agent-installer/AGENTS.md
new file mode 100644
index 00000000000..2ad4d9e1980
--- /dev/null
+++ b/dd-java-agent/agent-installer/AGENTS.md
@@ -0,0 +1,5 @@
+# agent-installer
+
+Module described in [ARCHITECTURE.md](../../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../../.agents/shared-module-guardrails.md).
diff --git a/dd-java-agent/agent-installer/CLAUDE.md b/dd-java-agent/agent-installer/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-java-agent/agent-installer/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-java-agent/agent-tooling/AGENTS.md b/dd-java-agent/agent-tooling/AGENTS.md
new file mode 100644
index 00000000000..70915012126
--- /dev/null
+++ b/dd-java-agent/agent-tooling/AGENTS.md
@@ -0,0 +1,5 @@
+# agent-tooling
+
+Module described in [ARCHITECTURE.md](../../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../../.agents/shared-module-guardrails.md).
diff --git a/dd-java-agent/agent-tooling/CLAUDE.md b/dd-java-agent/agent-tooling/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-java-agent/agent-tooling/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-java-agent/src/AGENTS.md b/dd-java-agent/src/AGENTS.md
new file mode 100644
index 00000000000..6ad3352a0f2
--- /dev/null
+++ b/dd-java-agent/src/AGENTS.md
@@ -0,0 +1,12 @@
+# dd-java-agent/src
+
+Module described in [ARCHITECTURE.md](../../ARCHITECTURE.md).
+
+> [!NOTE]
+> `dd-java-agent` both assembles the agent jar and owns startup code under `src`.
+> This layout does not follow Idiomatic Gradle's separation of code modules and aggregation projects:
+> startup code lives in the parent project rather than in a dedicated subproject.
+> These instructions therefore live under `src` to cover startup code and its tests without applying
+> the same guardrails to every product and instrumentation subproject.
+
+Read and follow the [shared module guardrails](../../.agents/shared-module-guardrails.md).
diff --git a/dd-java-agent/src/CLAUDE.md b/dd-java-agent/src/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-java-agent/src/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-trace-api/AGENTS.md b/dd-trace-api/AGENTS.md
new file mode 100644
index 00000000000..a2874c71be3
--- /dev/null
+++ b/dd-trace-api/AGENTS.md
@@ -0,0 +1,5 @@
+# dd-trace-api
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/dd-trace-api/CLAUDE.md b/dd-trace-api/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-trace-api/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/dd-trace-core/AGENTS.md b/dd-trace-core/AGENTS.md
new file mode 100644
index 00000000000..b89d9e78ffc
--- /dev/null
+++ b/dd-trace-core/AGENTS.md
@@ -0,0 +1,5 @@
+# dd-trace-core
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/dd-trace-core/CLAUDE.md b/dd-trace-core/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/dd-trace-core/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/internal-api/AGENTS.md b/internal-api/AGENTS.md
new file mode 100644
index 00000000000..fd5541a184b
--- /dev/null
+++ b/internal-api/AGENTS.md
@@ -0,0 +1,5 @@
+# internal-api
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/internal-api/CLAUDE.md b/internal-api/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/internal-api/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/remote-config/AGENTS.md b/remote-config/AGENTS.md
new file mode 100644
index 00000000000..ffcb2a3349a
--- /dev/null
+++ b/remote-config/AGENTS.md
@@ -0,0 +1,5 @@
+# remote-config
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/remote-config/CLAUDE.md b/remote-config/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/remote-config/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/telemetry/AGENTS.md b/telemetry/AGENTS.md
new file mode 100644
index 00000000000..f193ea1ac3c
--- /dev/null
+++ b/telemetry/AGENTS.md
@@ -0,0 +1,5 @@
+# telemetry
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/telemetry/CLAUDE.md b/telemetry/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/telemetry/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md
diff --git a/utils/AGENTS.md b/utils/AGENTS.md
new file mode 100644
index 00000000000..24490a1a1af
--- /dev/null
+++ b/utils/AGENTS.md
@@ -0,0 +1,5 @@
+# utils
+
+Module described in [ARCHITECTURE.md](../ARCHITECTURE.md).
+
+Read and follow the [shared module guardrails](../.agents/shared-module-guardrails.md).
diff --git a/utils/CLAUDE.md b/utils/CLAUDE.md
new file mode 100644
index 00000000000..43c994c2d36
--- /dev/null
+++ b/utils/CLAUDE.md
@@ -0,0 +1 @@
+@AGENTS.md