refactor(agent): remove Vercel adapter dead aliases

[mmabrouk]

This PR is part of a stack. Review bottom-up.

Each PR's diff is only its own delta. Merge from the bottom. This PR's base is #4765 (merge that first).

• feat(agent): Pi-backed agent workflow service, template, and tracing #4758: Pi-backed agent workflow service, template, tracing
• feat(agent): runnable tools as agent configuration #4759: runnable tools as agent configuration
• feat(agent): drive harnesses over ACP via the rivet sandbox-agent #4760: drive harnesses over ACP via rivet
• feat(agent): move the agent runtime into the SDK behind backend/harness ports #4761: move the runtime into the SDK behind backend/harness ports
  • chore(agent): docker cleanups for the sandbox-agent sidecar #4762: docker cleanups for the sidecar (side branch off feat(agent): move the agent runtime into the SDK behind backend/harness ports #4761)
• feat(sdk): typed agent tool resolution contracts #4763: typed SDK agent tool contracts
• feat(agent): resolve typed tools through the service #4764: resolve typed tools through the service
• feat(agent): deliver resolved tools through the runner #4765: deliver resolved tools through the runner
• refactor(agent): remove Vercel adapter dead aliases #4766: remove Vercel adapter dead aliases <- you are here
• fix(agent): propagate messages session ids to runner traces #4767: propagate messages session ids to runner traces
• feat(agent): route load-session through a no-op session store port #4768: load-session via a no-op session store port
• feat(sdk): advertise Vercel messages protocol headers #4769: advertise Vercel messages protocol headers
• docs(agent): agent-workflows ground truth + comment hygiene #4770: agent-workflows ground truth + comment hygiene

Context

The Vercel adapter moved into its own package (agents/adapters/vercel/). That move left behind a set of compatibility shims: underscore-prefixed aliases and re-exports that pointed back at the new canonical names. Nothing reads them anymore. This PR base is feat/sdk-local-tools-runner-docs. It is slice #2 (protocol shell hardening) of docs/design/agent-workflows/pr-stack.md, the dead-code removal step.

What this changes

This deletes the leftover aliases. The canonical functions stay exactly where they are. No call site changes, no behavior changes. The diff is one trimmed import plus the removed shim lines.

Key architectural decision to review

The only thing to confirm is that the removed names have no live callers. Here is what was removed and where it lived:

• _resolve_session_id and _inject_stream_session_id: compatibility wrappers in sdks/python/agenta/sdk/decorators/routing.py. The real helpers are resolve_session_id and inject_stream_session_id in the Vercel adapter.
• _VERCEL_UI_MESSAGE_STREAM_HEADERS and _vercel_sse_stream: self-aliases at the bottom of sdks/python/agenta/sdk/agents/adapters/vercel/sse.py. The canonical names VERCEL_UI_MESSAGE_STREAM_HEADERS and vercel_sse_stream are untouched.
• vercel_ui_messages_to_messages, message_to_vercel_ui_message, and agent_run_to_vercel_parts: re-exports trimmed from sdks/python/agenta/sdk/agents/ui_messages.py. These names still live in the adapter package and are imported directly from there.

One subtlety worth a second look: decorators/routing.py imports the canonical sse.py names and locally re-aliases them with as _VERCEL_UI_MESSAGE_STREAM_HEADERS and as _vercel_sse_stream. That local alias is separate from the deleted self-aliases inside sse.py, so it keeps working.

How to review this PR

Grep the codebase for each removed name and confirm zero live callers, then approve. The removed underscore wrappers have no callers. The trimmed ui_messages.py re-exports have no importers that go through ui_messages; every caller imports the canonical names directly from agents.adapters.vercel. This is safe to approve quickly.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
agenta-documentation	Ready	Preview, Comment	Jun 19, 2026 3:42pm

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[mmabrouk]

Reviewer guide: interesting code

This PR only deletes dead shims. I grepped the whole repo for each removed name to confirm no live caller. Results below.

• sdks/python/agenta/sdk/decorators/routing.py:37-46 — the _resolve_session_id and _inject_stream_session_id wrappers used to sit here. Grep for \b_resolve_session_id\b and \b_inject_stream_session_id\b returns zero callers. (The one hit for _resolve_session_id is a test function name, test_resolve_session_id_..., not a call.)

• sdks/python/agenta/sdk/agents/adapters/vercel/sse.py:19 — the _VERCEL_UI_MESSAGE_STREAM_HEADERS and _vercel_sse_stream self-aliases used to follow the canonical defs here. No module imports these underscore names from sse.py. The two hits in decorators/routing.py import the canonical names and apply their own local as _... alias, which is separate and untouched.

• sdks/python/agenta/sdk/agents/ui_messages.py:9 — the trimmed re-exports vercel_ui_messages_to_messages, message_to_vercel_ui_message, and agent_run_to_vercel_parts. Grep shows zero importers reach these via ui_messages. Every caller (including services/oss/src/agent/app.py and the unit tests) imports the canonical names directly from agents.adapters.vercel, where they still live.

Net: all removed names are dead at their old locations, and the canonical functions are unchanged. Safe to approve quickly.

[mmabrouk]

Trimmed to import only register_agent_message_routes. The dropped resolve_session_id/inject_stream_session_id were only fed into the now-deleted underscore wrappers below, so nothing else needed them.

[mmabrouk]

This module is now a thin facade over the three names callers actually use through it. The dropped re-exports (vercel_ui_messages_to_messages, message_to_vercel_ui_message, agent_run_to_vercel_parts) had no importers via ui_messages; callers reach them straight from agents.adapters.vercel.

[mmabrouk]

Superseded. Replacing the path-based stack with PRs sliced by functional area showing final code only, so reviewers don't comment on intermediate scaffolding that a later PR rewrites. See the new set.