Java: preserve MCP fields in PermissionRequest extensionData

Summary

The Java SDK drops MCP permission request fields during deserialization, so applications cannot safely approve a scoped MCP request.

Root cause

java/src/main/java/com/github/copilot/rpc/PermissionRequest.java declares:

@JsonIgnoreProperties(ignoreUnknown = true)
public class PermissionRequest {
    @JsonProperty("kind")
    private String kind;
    // ...
    private Map<String, Object> extensionData;
}

There is no @JsonAnySetter (or equivalent custom deserialization) to populate extensionData. Consequently, MCP fields outside the typed properties are discarded.

Reproduction

With copilot-sdk-java 1.0.8 and 1.0.9-preview.3, an MCP permission callback receives kind=mcp, but getExtensionData() is null:

sessionConfig.setOnPermissionRequest(request -> {
    System.out.println(request.getKind());          // mcp
    System.out.println(request.getExtensionData()); // null
    return PermissionResult.deny();
});

The incoming MCP request includes the details needed for a scoped decision:

{
  "permissionRequest": {
    "kind": "mcp",
    "serverName": "playwright",
    "toolName": "playwright-browser_navigate",
    "args": { "url": "http://127.0.0.1:8106/docs/target-app/" }
  }
}

A handler that must enforce an exact server, tool, and URL therefore rejects every request. Approving all MCP requests is not an equivalent security boundary.

Expected behavior

Preserve unknown MCP fields in PermissionRequest.extensionData, including nested args, so permission handlers can enforce exact server/tool/argument allowlists.

Suggested test

Add a Java deserialization test that passes an MCP permission payload through PermissionRequest.fromJsonValue() and verifies extensionData retains serverName, toolName, and args.url.

Affected versions

copilot-sdk-java 1.0.8
copilot-sdk-java 1.0.9-preview.3

Originally filed in github/copilot-sdk-java, but this monorepo owns the affected Java source.

Investigation findings

Confirmed bug — the reported behaviour reproduces exactly as described.

What I looked at

java/src/main/java/com/github/copilot/rpc/PermissionRequest.java — the class that deserializes incoming permission-request payloads
java/src/test/java/com/github/copilot/DataObjectCoverageTest.java — the existing setter-coverage test

Root cause

PermissionRequest declares extensionData but had no @JsonAnySetter method. Jackson therefore honoured @JsonIgnoreProperties(ignoreUnknown = true) and silently discarded every field that wasn't one of the three typed properties (kind, toolCallId, managedApprovalRequired). MCP-specific fields — serverName, toolName, and args — were all lost at deserialization time, leaving getExtensionData() always null.

Fix applied (commit `3b27cb3`)

Added @JsonAnySetter — a new setExtensionDataEntry(String key, Object value) method now captures every unknown property into extensionData, so serverName, toolName, and args are all preserved.
Initialized extensionData to a LinkedHashMap at field level so the map is never null after deserialization.
Added a regression test in DataObjectCoverageTest that round-trips a realistic MCP permission JSON payload and asserts all three MCP fields (including the nested args.url) are present in getExtensionData().

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

repo.maven.apache.org

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "repo.maven.apache.org"

See Network Configuration for more information.

Generated by Bug Handler for #2273 · sonnet46 48.8 AIC · ⌖ 5.16 AIC · ⊞ 5.9K · ◷

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Java: preserve MCP fields in PermissionRequest extensionData #2273

Summary

Root cause

Reproduction

Expected behavior

Suggested test

Affected versions

Investigation findings

What I looked at

Root cause

Fix applied (commit `3b27cb3`)

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Java: preserve MCP fields in PermissionRequest extensionData #2273

Description

Summary

Root cause

Reproduction

Expected behavior

Suggested test

Affected versions

Activity

github-actions commented on Aug 5, 2026

Investigation findings

What I looked at

Root cause

Fix applied (commit 3b27cb3)

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Fix applied (commit `3b27cb3`)