Add SDK support for agent selection and session compaction APIs

[SteveSandersonMS]

Summary

Add SDK support for the new agent selection and session compaction JSON-RPC APIs added to the Copilot CLI runtime.

New RPC APIs

Agent selection (session.agent.*):

• list — List available custom agents
• getCurrent — Get the currently selected agent
• select — Select a custom agent by name
• deselect — Deselect the current agent

Session compaction (session.compaction.*):

• compact — Compact session history to reduce token usage

Changes

• Code generation: Regenerated RPC types for all 4 SDKs (Node.js, Python, Go, .NET) from updated \�pi.schema.json\
• C# codegen fix: Request class names now use the full RPC method path (e.g., \SessionAgentListRequest) to avoid name collisions between APIs that share method names like \list\
• Snapshot normalization: Added \\ normalizer in the replaying CAPI proxy to keep compaction snapshots concise
• E2E tests: Added 6 tests per language (24 total) covering all agent and compaction APIs

Test results

All 24 e2e tests pass across all 4 languages:

• Node.js: 6/6 ✅
• Python: 6/6 ✅
• Go: 6/6 ✅
• .NET: 6/6 ✅

Companion PR

Cannot merge or pass E2E tests until a corresponding runtime change (3538) is merged and an updated package is shipped.

[github-actions]

Cross-SDK Consistency Review ✅

I've reviewed PR #544 for consistency across all four SDK implementations (Node.js/TypeScript, Python, Go, and .NET). This PR demonstrates excellent cross-language consistency.

Summary

This PR adds two new RPC API families to all SDKs:

• Agent Selection APIs (session.agent.*): list, getCurrent, select, deselect
• Session Compaction API (session.compaction.compact): compact session history

✅ Consistency Findings

1. API Structure & Naming — Excellent consistency across all languages:

Language	Access Pattern	Method Names
Node.js	session.rpc.agent.list()	list(), getCurrent(), select(), deselect(), compact()
Python	session.rpc.agent.list()	list(), get_current(), select(), deselect(), compact()
Go	session.RPC.Agent.List()	List(), GetCurrent(), Select(), Deselect(), Compact()
.NET	session.Rpc.Agent.ListAsync()	ListAsync(), GetCurrentAsync(), SelectAsync(), DeselectAsync(), CompactAsync()

All naming follows the appropriate language conventions:

• TypeScript: camelCase for methods ✅
• Python: snake_case for methods ✅
• Go: PascalCase for exported methods ✅
• .NET: PascalCase with Async suffix ✅

2. Test Coverage — Complete parity:

All 4 SDKs include identical test scenarios (6 tests per language = 24 total):

Agent Selection tests:

• should list available custom agents
• should return null when no agent is selected
• should select and get current agent
• should deselect current agent
• should return empty list when no custom agents configured

Compaction test:

• should compact session history after messages

3. Generated Code — Consistent implementation:

All SDKs properly:

• Generate RPC request/result classes from the schema
• Expose agent/compaction APIs under session.rpc.*
• Use the same underlying RPC method names ("session.agent.list", etc.)

4. C# Codegen Improvement — Good fix:

The change to use typeToClassName(method.rpcMethod) instead of methodName for request class names (e.g., SessionAgentListRequest instead of ListRequest) prevents naming collisions. This is a good defensive improvement that maintains consistency with the full RPC method path.

5. Test Infrastructure — Properly maintained:

• Added snapshot normalization for compaction prompts in the replay proxy
• All tests use the shared E2E test harness correctly
• Snapshot files follow existing patterns

🎯 Conclusion

No consistency issues found. This PR maintains excellent feature parity across all four SDK implementations. The APIs are semantically identical, with only appropriate language-specific naming adaptations. Great work! 🚀

AI generated by SDK Consistency Review Agent

[Copilot]

Pull request overview

Adds cross-SDK support (Node.js, Python, Go, .NET) for new Copilot CLI JSON-RPC APIs covering agent selection (session.agent.*) and session compaction (session.compaction.*), along with replay-proxy normalization and new E2E coverage.

Changes:

• Regenerates RPC types across SDKs and extends session-scoped RPC clients with agent and compaction APIs.
• Updates C# codegen to avoid request-type name collisions by using full RPC method paths in request class names.
• Adds/updates replay-proxy normalization and YAML snapshots, plus new E2E tests for agent selection and compaction RPCs.

Reviewed changes

Copilot reviewed 9 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/snapshots/compaction/should_trigger_compaction_with_low_threshold_and_emit_events.yaml	Updates compaction snapshot to use ${compaction_prompt} and refreshes expected conversation flow.
test/snapshots/agent_and_compact_rpc/should_compact_session_history_after_messages.yaml	New snapshot covering session.compaction.compact RPC flow.
test/harness/replayingCapiProxy.ts	Normalizes the verbose compaction-summary prompt into ${compaction_prompt} for stable snapshots.
scripts/codegen/csharp.ts	Uses full RPC method path for generated C# request class names to prevent collisions.
python/e2e/test_agent_and_compact_rpc.py	Adds Python E2E tests for agent selection + compaction RPCs.
python/copilot/generated/rpc.py	Adds generated Python RPC types + APIs for agent and compaction.
nodejs/test/e2e/agent_and_compact_rpc.test.ts	Adds Node.js E2E tests for agent selection + compaction RPCs.
nodejs/src/generated/rpc.ts	Adds generated Node session RPC bindings and types for agent and compaction.
go/rpc/generated_rpc.go	Adds generated Go RPC types + Agent/Compaction RPC APIs on SessionRpc.
go/internal/e2e/agent_and_compact_rpc_test.go	Adds Go E2E tests for agent selection + compaction RPCs.
dotnet/test/AgentAndCompactRpcTests.cs	Adds .NET E2E tests for agent selection + compaction RPCs.
dotnet/src/Generated/Rpc.cs	Adds generated .NET RPC types + APIs for agent and compaction, and updates request-type names.

[github-actions]

✅ Cross-SDK Consistency Review: Excellent

I've reviewed this PR for consistency across all four SDK implementations (Node.js/TypeScript, Python, Go, and .NET), and I'm pleased to report that this change demonstrates exemplary cross-language parity.

What I Verified

1. API Methods ✅

All 4 SDKs expose the same agent selection and session compaction APIs with language-appropriate naming:

Agent Selection APIs:

• Node.js: session.rpc.agent.list(), getCurrent(), select(), deselect()
• Python: session.rpc.agent.list(), get_current(), select(), deselect()
• Go: session.RPC.Agent.List(), GetCurrent(), Select(), Deselect()
• .NET: session.Rpc.Agent.ListAsync(), GetCurrentAsync(), SelectAsync(), DeselectAsync()

Session Compaction API:

• Node.js: session.rpc.compaction.compact()
• Python: session.rpc.compaction.compact()
• Go: session.RPC.Compaction.Compact()
• .NET: session.Rpc.Compaction.CompactAsync()

The naming follows each language's conventions (camelCase for JS, snake_case for Python, PascalCase for exported Go/C# identifiers).

2. Type Definitions ✅

Generated RPC types are semantically equivalent across all languages:

• SessionAgentListResult, SessionAgentGetCurrentResult, SessionAgentSelectResult, SessionAgentDeselectResult
• SessionCompactionCompactResult with fields: success: boolean, tokensRemoved: number, messagesRemoved: number

All types properly handle nullable values (e.g., agent can be null in GetCurrent when no agent is selected).

3. E2E Test Coverage ✅

All 4 SDKs have identical test scenarios (6 tests each, 24 total):

Agent Selection Tests:

1. ✅ List available custom agents
2. ✅ Return null when no agent is selected
3. ✅ Select and get current agent
4. ✅ Deselect current agent
5. ✅ Return empty list when no custom agents configured

Compaction Test:
6. ✅ Compact session history after messages

Each test verifies the same behavior and assertions, ensuring feature parity.

4. Code Generation Improvements ✅

• C# codegen enhancement: Request classes use full RPC method paths (e.g., SessionAgentListRequest) to avoid name collisions
• Nullable type handling: Proper anyOf: [T, null] → T? mapping in C# codegen
• All SDKs regenerated from the same api.schema.json source

Summary

This PR is a model example of maintaining cross-SDK consistency:

• ✅ Complete feature parity across all 4 languages
• ✅ Idiomatic naming following each language's conventions
• ✅ Comprehensive E2E test coverage with parallel test scenarios
• ✅ Proper code generation from shared schema definitions

No consistency issues found. The implementation maintains the high standard of this multi-language SDK repository.

Great work, @SteveSandersonMS! 🎉

AI generated by SDK Consistency Review Agent