[chore] Remove the pi_agenta harness experiment

docs/design/agent-workflows/documentation/adapters/pi.md

@@ -10,7 +10,7 @@ pages first. This page assumes the relay and the wire contract.
 ## How Pi runs
 
 Pi runs over ACP, through sandbox-agent (`engines/sandbox_agent.ts`). The harness value
-`pi_core` (plain Pi) and `pi_agenta` (Pi with Agenta's forced opinion) both map to the `pi`
+`pi_core` (and the legacy `pi_agenta` spelling of a removed experiment) both map to the `pi`
 ACP agent. This is the one engine the runner has. The sandbox-agent daemon starts the
 `pi-acp` adapter, which starts the `pi` CLI.
 

docs/design/agent-workflows/documentation/agent-configuration.md

@@ -104,7 +104,7 @@ Its fields and defaults:
 | `model` | `str` | `"gpt-5.5"` | `x-parameter: grouped_choice`, plain string |
 | `tools` | `List[ToolConfig]` | empty list | typed discriminated union |
 | `mcp_servers` | `List[MCPServerConfig]` | empty list | typed |
-| `harness` | `Literal["pi_core","claude","pi_agenta"]` | `"pi_core"` | enum |
+| `harness` | `Literal["pi_core","claude","codex"]` | `"pi_core"` | enum |
 | `sandbox` | `Literal["local","daytona"]` | `"local"` | enum |
 | `runner.permissions.default` | `Literal["allow","ask","deny","allow_reads"]` | `"allow_reads"` | enum, four modes |
 
@@ -218,23 +218,20 @@ Legend: (a) catalog/schema, (b) SDK neutral config, (c) runtime.
 | model / provider | yes, `model: str` | yes, `Optional[str]` | wired to the runner | Loose string. No `ModelRef`, no provider enum. There is no separate provider field. |
 | tools | yes, strict list | yes, lenient coercion | wired, resolved to builtin names + tool specs | Entries strict, list lenient. The shipped default template fills it with Pi's four default built-ins (`read`, `bash`, `edit`, `write`); see [Tools](tools.md). |
 | mcp_servers | yes, strict list | yes | wired, resolved to runner MCP servers | Strict per entry. Claude supports external HTTP servers; Pi refuses them until its bridge exists. |
-| skills | yes, embed/inline list | yes | wired | Author-settable (`SkillConfig` inline or `@ag.embed` references). The playground build-kit overlay embeds one skill, the `build-an-agent` playbook; the `pi_agenta` harness additionally force-unions `getting-started`. See below. |
-| persona | no | no | wired but forced only | Not a config field. The Agenta harness hardcodes an append-system preamble. See below. |
+| skills | yes, embed/inline list | yes | wired | Author-settable (`SkillConfig` inline or `@ag.embed` references). The playground build-kit overlay embeds one skill, the `build-an-agent` playbook. See below. |
+| persona | no | no | removed | Not a config field. It was the removed `pi_agenta` harness's hardcoded append-system preamble. See below. |
 | agents_md | yes, `agents_md: str` | yes, as `instructions` | wired to `agentsMd` | The schema names it `agents_md`. The neutral config names it `instructions`. |
 | harness | yes, enum | yes, on `AgentConfig` | wired, picks the harness class | Enum-enforced. The runtime validates via `make_harness`. |
 | sandbox | yes, enum | yes, on `AgentConfig` | wired to the backend, absent from `SessionConfig` | Backend concern, not agent identity. |
 | runner.permissions.default | yes, enum (4 modes) | yes, as `permission_default` on `AgentConfig` | wired to `SessionConfig` and the run request's `permissions.default` | Enforced for both harnesses: Claude at its settings file and the ACP responder, Pi at the tool relay. No longer decorative on Pi. |
 
 ## Notable gaps and quirks
 
-`persona` is not author config; it is a runtime injection of the Agenta harness only (a forced
-append-system string). `skills` used to work the same way, but is author config now: inline
-`SkillConfig` packages or `@ag.embed` references the backend inlines before the runner sees
-them. Two platform skills still arrive without the author writing anything: the playground
-build-kit overlay embeds the `build-an-agent` playbook, and the `pi_agenta` harness
-force-unions the `getting-started` skill (`AGENTA_FORCED_SKILLS` in
-`sdks/python/agenta/sdk/agents/adapters/agenta_builtins.py`). Each is delivered exactly once.
-Pi (`pi_core`) and Claude harnesses get no forced skills or persona.
+`persona` is gone with the removed `pi_agenta` harness (it was that harness's forced
+append-system string). `skills` is author config: inline `SkillConfig` packages or
+`@ag.embed` references the backend inlines before the runner sees them. One platform skill
+still arrives without the author writing anything: the playground build-kit overlay embeds
+the `build-an-agent` playbook. No harness forces skills or a persona.
 
 Per-harness divergence is real in other ways, but not in permission enforcement anymore: the
 permission policy is now enforced on both Claude and Pi. Builtin tool names are dropped for

docs/design/agent-workflows/documentation/architecture.md

@@ -13,8 +13,8 @@ The runtime keeps two run choices configurable as fields on `AgentConfig`
 (`sdks/python/agenta/sdk/agents/dtos.py`):
 
 - **Harness:** which agent runs. Supported values are `pi_core`, `claude`, and experimental
-  `pi_agenta`. Default `pi_core`. `pi_core` and `pi_agenta` both drive the `pi` ACP agent;
-  `pi_agenta` is Pi with Agenta's forced opinion.
+  Default `pi_core`, which drives the `pi` ACP agent. (`pi_agenta`, a removed experiment,
+  is still read as `pi_core` so old stored configs run.)
 - **Sandbox:** where the run happens. Supported values are `local` and `daytona`. Default
   `local`.
 
@@ -66,11 +66,12 @@ and tool credentials and passes them only in the scoped `/run` payloads that nee
 
 The deployed handler always uses `SandboxAgentBackend`. `select_backend` in
 `services/oss/src/agent/app.py:49` constructs `SandboxAgentBackend` for every run, regardless
-of harness. So `pi_core`, `claude`, and `pi_agenta` all run through the sandbox-agent daemon
+of harness. So `pi_core`, `claude`, and `codex` all run through the sandbox-agent daemon
 over ACP.
 
 The runner has one engine, the sandbox-agent ACP path (`engines/sandbox_agent.ts`). The
-`harness` field on the `/run` request selects the ACP agent: `pi_core` and `pi_agenta` both
+`harness` field on the `/run` request selects the ACP agent: `pi_core` (and the legacy
+`pi_agenta` spelling) both
 map to the `pi` ACP agent, `claude` maps to `claude`. There is no engine selector on the wire.
 A legacy in-process Pi engine and an `InProcessPiBackend` adapter existed during the POC; both
 were removed.
@@ -82,23 +83,22 @@ The SDK runtime models engines as `Backend` adapters
 
 | Backend | Status | Harnesses | Sandbox support | Notes |
 | --- | --- | --- | --- | --- |
-| `SandboxAgentBackend` | Implemented | `pi_core`, `claude`, `pi_agenta` | `local`, `daytona` | The deployed path and the only engine. Drives `engines/sandbox_agent.ts`: starts the sandbox-agent daemon and an ACP adapter. `supported_harnesses` is `{pi_core, claude, pi_agenta}` (`adapters/sandbox_agent.py:121`). |
+| `SandboxAgentBackend` | Implemented | `pi_core`, `claude`, `codex` | `local`, `daytona` | The deployed path and the only engine. Drives `engines/sandbox_agent.ts`: starts the sandbox-agent daemon and an ACP adapter. `supported_harnesses` is `{pi_core, claude, codex}` (`adapters/sandbox_agent.py`). |
 | `LocalBackend` | Not implemented | Intended: `pi_core`, `claude` | Local machine | Public class exists; `create_sandbox` and `create_session` raise `NotImplementedError` (`adapters/local.py:34`). |
 
 ## Harnesses
 
 The SDK runtime models agent-specific behavior as `Harness` adapters
 (`sdks/python/agenta/sdk/agents/adapters/harnesses.py`). The Python class names are unchanged;
 only the harness string values changed (`HarnessType.PI` is `"pi_core"`, `HarnessType.AGENTA`
-is `"pi_agenta"`, `HarnessType.CLAUDE` is `"claude"`).
+is removed, `HarnessType.CLAUDE` is `"claude"`).
 
 | Harness | Value | Status | Notes |
 | --- | --- | --- | --- |
 | `PiHarness` | `pi_core` | Implemented | Native Pi tools, Pi prompt overrides, Pi tracing extension. Drives the `pi` ACP agent. |
 | `ClaudeHarness` | `claude` | Implemented | MCP-delivered tools, permission policy, runner-built tracing. No Pi built-in tools. Drives the `claude` ACP agent. |
-| `AgentaHarness` | `pi_agenta` | Experimental | Pi with forced tools, forced skills, a base AGENTS.md preamble, and a persona. Drives the `pi` ACP agent plus forced extras. Content is still placeholder. |
 
-The `pi_agenta` harness runs on the sandbox-agent path. The runner treats it as the `pi` ACP
+The removed `pi_agenta` value still reads as the `pi` ACP
 agent and layers the forced skills and prompt extras on top
 (`services/agent/src/engines/sandbox_agent/run-plan.ts`). The QA matrix verified it on
 sandbox-agent local and Daytona (`projects/qa/findings.md`, F-002).

docs/design/agent-workflows/documentation/skills.md

@@ -67,7 +67,7 @@ says.
 
 `agent-workflows-qa` (shared) defines the test matrix for the agent runtime. Its three axes
 are the environment (sandbox-agent local, sandbox-agent Daytona, and the local SDK), the
-harness (`pi_core`, `pi_agenta`, `claude`), and the capability under test. "Test with daytona,
+harness (`pi_core`, `claude`, `codex`), and the capability under test. "Test with daytona,
 local pi, and claude, on both the SDK and the UI" is exactly a walk across these cells. Each
 test forces a capability with a token the model cannot guess, so a pass proves the capability
 ran.

docs/docs/reference/agents/01-agent-configuration.mdx

@@ -59,7 +59,7 @@ Which providers, deployments, and connection modes each harness can reach is ser
 GET /api/workflows/catalog/harnesses/{harness}
 ```
 
-In the shipped table, `pi_core` and `pi_agenta` reach `openai`, `anthropic`, `gemini`, `mistral`, `groq`, `minimax`, `together_ai`, and `openrouter`, with deployments `direct` and `custom`. `claude` reaches `anthropic` only, with deployments `direct`, `custom`, `bedrock`, and `vertex_ai`, and selects its model by alias rather than by a `provider/model` string.
+In the shipped table, `pi_core` reaches `openai`, `anthropic`, `gemini`, `mistral`, `groq`, `minimax`, `together_ai`, and `openrouter`, with deployments `direct` and `custom`. `claude` reaches `anthropic` only, with deployments `direct`, `custom`, `bedrock`, and `vertex_ai`, and selects its model by alias rather than by a `provider/model` string.
 
 ## tools
 
@@ -195,18 +195,17 @@ Each entry is an inline skill package. See [Skills](/concepts/skills).
 
 | Field | Type | Required | Default | Description |
 |---|---|---|---|---|
-| `kind` | `"pi_core"` \| `"pi_agenta"` \| `"claude"` \| `"codex"` | No | `"pi_core"` | Which coding agent to drive. |
+| `kind` | `"pi_core"` \| `"claude"` \| `"codex"` | No | `"pi_core"` | Which coding agent to drive. |
 | `permissions` | object | No | see [harness.permissions](#harnesspermissions) | Tool-use gating posture, applied by harnesses that gate. |
 | `extras` | object | No | `{}` | Per-harness knobs passed through unchanged. For Pi, `system` replaces the base system prompt and `append_system` adds to it. Both are independent of `instructions.agents_md`. |
 
 | `kind` | Display name | Versioned slug |
 |---|---|---|
 | `pi_core` | Pi | `agenta:harness:pi_core:v0` |
-| `pi_agenta` | Pi (Agenta) | `agenta:harness:pi_agenta:v0` |
 | `claude` | Claude Code | `agenta:harness:claude:v0` |
 | `codex` | Codex | `agenta:harness:codex:v0` |
 
-`pi_agenta` runs the same engine as `pi_core` with Agenta's own skills, tools, and base instructions forced on.
+`pi_agenta` was an experimental Pi variant, removed in August 2026. A stored config that still carries the value runs as `pi_core`.
 
 ### harness.permissions
 

sdks/python/agenta/__init__.py

@@ -56,7 +56,6 @@
 # `agenta.Message` already names the prompt message type; import the agents one from
 # `agenta.sdk.agents` when needed.
 from .sdk.agents import (  # noqa: F401
-    AgentaHarness,
     AgentTemplate,
     ClaudeHarness,
     Environment,

sdks/python/agenta/sdk/agents/__init__.py

@@ -21,7 +21,6 @@
 """
 
 from .adapters import (
-    AgentaHarness,
     ClaudeHarness,
     CodexHarness,
     LocalBackend,
@@ -55,7 +54,6 @@
     UnsupportedProviderError,
 )
 from .dtos import (
-    AgentaAgentTemplate,
     AgentTemplate,
     AgentTemplateShapeError,
     Event,
@@ -166,7 +164,6 @@
     "PiAgentTemplate",
     "ClaudeAgentTemplate",
     "CodexAgentTemplate",
-    "AgentaAgentTemplate",
     "HarnessKind",
     "HarnessIdentity",
     "HARNESS_IDENTITIES",
@@ -284,6 +281,5 @@
     "PiHarness",
     "ClaudeHarness",
     "CodexHarness",
-    "AgentaHarness",
     "make_harness",
 ]

sdks/python/agenta/sdk/agents/adapters/__init__.py

@@ -2,15 +2,14 @@
 
 - Backend adapters: ``SandboxAgentBackend`` (sandbox-agent over ACP),
   ``LocalBackend`` (standalone SDK runs; not yet implemented).
-- Harness adapters: ``PiHarness``, ``ClaudeHarness``, ``CodexHarness``, ``AgentaHarness``
+- Harness adapters: ``PiHarness``, ``ClaudeHarness``, ``CodexHarness``
   (+ ``make_harness``).
 - HTTP/browser protocol adapters live in subpackages, e.g. ``adapters.vercel``.
 
 Shared plumbing for the runner-backed adapters lives in ``agents/utils``.
 """
 
 from .harnesses import (
-    AgentaHarness,
     ClaudeHarness,
     CodexHarness,
     PiHarness,
@@ -25,6 +24,5 @@
     "PiHarness",
     "ClaudeHarness",
     "CodexHarness",
-    "AgentaHarness",
     "make_harness",
 ]