---
phase: 04-security
plan: 03
type: execute
wave: 2
depends_on: ["04-01"]
files_modified:
  - cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SseConnectionManager.java
  - cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SsePayloadSigner.java
  - cameleer3-server-app/src/test/java/com/cameleer3/server/app/security/SseSigningIT.java
  - cameleer3-server-app/src/test/java/com/cameleer3/server/app/agent/SsePayloadSignerTest.java
autonomous: true
requirements:
  - SECU-04

must_haves:
  truths:
    - "All config-update, deep-trace, and replay SSE events carry a valid Ed25519 signature in the data JSON"
    - "Signature is computed over the payload JSON without the signature field, then added as a 'signature' field"
    - "Agent can verify the signature using the public key received at registration"
  artifacts:
    - path: "cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SsePayloadSigner.java"
      provides: "Component that signs SSE command payloads before delivery"
    - path: "cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SseConnectionManager.java"
      provides: "Updated onCommandReady with signing before sendEvent"
  key_links:
    - from: "SseConnectionManager.onCommandReady"
      to: "SsePayloadSigner.signPayload"
      via: "Signs payload before SSE delivery"
      pattern: "ssePayloadSigner\\.signPayload"
    - from: "SsePayloadSigner"
      to: "Ed25519SigningService.sign"
      via: "Delegates signing to Ed25519 service"
      pattern: "ed25519SigningService\\.sign"
---

<objective>
Add Ed25519 signature to all SSE command payloads (config-update, deep-trace, replay) before delivery. The signature is computed over the data JSON and included as a `signature` field in the event data, enabling agents to verify payload integrity using the server's public key.

Purpose: Ensures all pushed configuration and commands are integrity-protected, so agents can trust the payloads they receive.
Output: All SSE command events carry verifiable Ed25519 signatures.
</objective>

<execution_context>
@C:/Users/Hendrik/.claude/get-shit-done/workflows/execute-plan.md
@C:/Users/Hendrik/.claude/get-shit-done/templates/summary.md
</execution_context>

<context>
@.planning/PROJECT.md
@.planning/ROADMAP.md
@.planning/STATE.md
@.planning/phases/04-security/04-CONTEXT.md
@.planning/phases/04-security/04-RESEARCH.md
@.planning/phases/04-security/04-01-SUMMARY.md

@cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SseConnectionManager.java

<interfaces>
<!-- From Plan 01 (will exist after execution): -->

From core/security/Ed25519SigningService.java:
```java
public interface Ed25519SigningService {
    String sign(String payload);        // Returns Base64-encoded signature
    String getPublicKeyBase64();        // Returns Base64-encoded X.509 public key
}
```

From app/agent/SseConnectionManager.java:
```java
@Component
public class SseConnectionManager implements AgentEventListener {
    // Key method to modify:
    public void onCommandReady(String agentId, AgentCommand command) {
        String eventType = command.type().name().toLowerCase().replace('_', '-');
        boolean sent = sendEvent(agentId, command.id(), eventType, command.payload());
        // command.payload() is a String (JSON)
    }

    public boolean sendEvent(String agentId, String eventId, String eventType, Object data) {
        // data is sent via SseEmitter.event().data(data, MediaType.APPLICATION_JSON)
    }
}
```

From core/agent/AgentCommand.java:
```java
public record AgentCommand(String id, CommandType type, String payload, String agentId, Instant createdAt, CommandStatus status) {
    // payload is a JSON string
}
```
</interfaces>
</context>

<tasks>

<task type="auto" tdd="true">
  <name>Task 1: SsePayloadSigner + signing integration in SseConnectionManager</name>
  <files>
    cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SsePayloadSigner.java,
    cameleer3-server-app/src/main/java/com/cameleer3/server/app/agent/SseConnectionManager.java,
    cameleer3-server-app/src/test/java/com/cameleer3/server/app/agent/SsePayloadSignerTest.java,
    cameleer3-server-app/src/test/java/com/cameleer3/server/app/security/SseSigningIT.java
  </files>
  <behavior>
    SsePayloadSigner unit tests:
    - signPayload(jsonString) returns a new JSON string containing all original fields plus a "signature" field
    - The "signature" field is a Base64-encoded Ed25519 signature
    - The signature is computed over the ORIGINAL JSON string (without signature field)
    - Signature verifies against the public key from Ed25519SigningService
    - null or empty payload returns the payload unchanged (defensive)

    SseSigningIT integration test:
    - Register an agent (with bootstrap token), get public key from response
    - Open SSE connection (with JWT query param)
    - Send a config-update command to the agent
    - Receive the SSE event and verify it contains a "signature" field
    - Verify the signature against the public key using JDK Ed25519 Signature.getInstance("Ed25519")
  </behavior>
  <action>
    1. Create `SsePayloadSigner` as a `@Component`:
       - Constructor takes `Ed25519SigningService` and `ObjectMapper`
       - `signPayload(String jsonPayload)` method:
         a. The payload JSON string IS the data to sign (sign the exact string)
         b. Compute signature: `ed25519SigningService.sign(jsonPayload)` returns Base64 signature
         c. Parse the JSON payload, add `"signature": signatureBase64` field, serialize back
         d. Return the signed JSON string
       - Handle edge cases: if payload is null or empty, return as-is with a log warning

    2. Update `SseConnectionManager`:
       - Add `SsePayloadSigner` as a constructor dependency
       - In `onCommandReady()`, sign the payload before sending:
         ```java
         String signedPayload = ssePayloadSigner.signPayload(command.payload());
         boolean sent = sendEvent(agentId, command.id(), eventType, signedPayload);
         ```
       - The `sendEvent` method already sends `data` as `MediaType.APPLICATION_JSON`. Since `signedPayload` is already a JSON string, the SseEmitter will serialize it. IMPORTANT: Since the payload is already a JSON string and SseEmitter will try to JSON-serialize it (wrapping in quotes), we need to send it as a pre-serialized value. Change `sendEvent` to use `.data(signedPayload)` without MediaType for signed payloads, OR parse it to a JsonNode/Map first so Jackson serializes it correctly. The cleanest approach: parse the signed JSON string into a `JsonNode` via `objectMapper.readTree(signedPayload)` and pass that as the data object -- Jackson will serialize the tree correctly.

    3. Write `SsePayloadSignerTest` (unit test, no Spring context):
       - Create a real `Ed25519SigningServiceImpl` and `ObjectMapper` for testing
       - Test cases per behavior spec above
       - Verify signature by using JDK `Signature.getInstance("Ed25519")` with the public key

    4. Write `SseSigningIT` (extends AbstractClickHouseIT):
       - Register agent using bootstrap token (from application-test.yml)
       - Extract `serverPublicKey` from registration response
       - Get JWT from registration response
       - Open SSE connection via `java.net.http.HttpClient` async API (same pattern as AgentSseControllerIT) with `?token=<jwt>`
       - Use the agent command endpoint to push a config-update command to the agent
       - Read the SSE event from the stream
       - Parse the event data JSON, extract the `signature` field
       - Reconstruct the unsigned payload (remove signature field, serialize)
       - Verify signature using `Signature.getInstance("Ed25519")` with the public key decoded from Base64
       - NOTE: This test depends on Plan 02's bootstrap token and JWT auth being in place. If Plan 03 executes before Plan 02, the test will need the TestSecurityHelper or a different auth approach. Since both are Wave 2 but independent, document this: "If Plan 02 is not yet complete, use TestSecurityHelper from Plan 01's temporary permit-all config."
  </action>
  <verify>
    <automated>cd /c/Users/Hendrik/Documents/projects/cameleer3-server && mvn test -pl cameleer3-server-app -Dtest="SsePayloadSignerTest,SseSigningIT" -Dsurefire.reuseForks=false</automated>
  </verify>
  <done>
    - SsePayloadSigner signs JSON payloads with Ed25519 and adds signature field
    - SseConnectionManager signs all command payloads before SSE delivery
    - Unit tests verify signature roundtrip (sign + verify with public key)
    - Integration test verifies end-to-end: command sent -> SSE event received with valid signature
    - Existing SSE tests still pass (ping events are not signed, only command events)
  </done>
</task>

</tasks>

<verification>
mvn clean verify
SsePayloadSigner unit tests pass. SseSigningIT integration test verifies end-to-end Ed25519 signing of SSE command events.
</verification>

<success_criteria>
- All SSE command events (config-update, deep-trace, replay) include a "signature" field
- Signature verifies against the server's Ed25519 public key
- Signature is computed over the payload JSON without the signature field
- Ping keepalive events are NOT signed (they are SSE comments, not data events)
- Existing SSE functionality unchanged (connection, ping, delivery tracking)
</success_criteria>

<output>
After completion, create `.planning/phases/04-security/04-03-SUMMARY.md`
</output>
