aish/docs/PHASE2.md

# aish — Phase 2 Manifest

**Project:** aish — AI-augmented conversational shell
**Document:** Phase 2 Requirements, Architecture & Design Decisions
**Status:** Analyze (formulate complete; live-probed against lmcp v0.5.4 + hossenfelder proxy)
**Date:** 2026-05-12

PHASE0.md is the locked substrate; PHASE1.md is layered on top. This
manifest specifies what Phase 2 adds. Section numbers reference back to
PHASE0.md / PHASE1.md where relevant.

---

## 1. Scope of Phase 2

Three pillars per PHASE0.md §11 row 2:

1. **MCP client** (`mcp.lua`) — JSON-RPC 2.0 over HTTP+SSE transport.
   Target reference implementation: `lmcp`. Operations needed for v1:
   `initialize`, `tools/list`, `tools/call`. Multiple servers may be
   connected concurrently; tools are namespaced `<server>.<tool>`.
2. **Tool-calling protocol bridge** — the broker sends OpenAI-compatible
   `tools` in the request body; the model emits `tool_calls` in the
   response; `mcp.lua` dispatches each call to the right server; the
   tool result is fed back as a `role:"tool"` turn in `context.lua` and
   the chat continues.
3. **Authorization gate** — `safety.lua` (PHASE0.md §4 stub) finally gets
   implemented. Every tool call is confirmed by the user by default,
   with per-tool and per-server `auto_approve` policies in `config.lua`.

**Phase 2 is done when:**

- aish can connect to at least one local `lmcp` server declared in
  `config.lua` and one connected via `:mcp connect <url>` at runtime.
- `:mcp list` shows connected servers; `:mcp tools` shows discovered
  tools across all servers.
- A model conversation can invoke a tool: the broker request carries
  the live tools schema; the response's `tool_calls` are confirmed by
  the user; each call dispatches to the right MCP server; the result
  re-enters the chat; the model continues with the result available.
- `CMD:` extraction (PHASE0.md §6 substrate invariant) still works
  unchanged — Phase 2 is additive, not replacing.
- A tool with `auto_approve = true` (in config) executes without the
  confirm prompt; a non-approved tool still prompts.

---

## 2. Technology Decisions (delta from Phase 1)

| Decision | Choice | Rationale |
|---|---|---|
| MCP transport | HTTP POST per RPC, `Connection: close` per response, **no long-lived SSE GET channel** in v1 | Analyze finding (2026-05-12): lmcp v0.5.4 only implements the trivial POST-and-respond flavor of the spec's streamable-HTTP transport. Its GET /mcp endpoint announces the POST endpoint then closes — there's no server→client notification channel to listen on. Combined with lmcp's `capabilities.tools.listChanged = false`, aish doesn't need an SSE GET listener at all for lmcp. Stdio transport is left for a possible Phase 2.1 if a stdio-only MCP server becomes necessary. |
| MCP protocol version | `2025-03-26` (confirmed by live probe of boltzmann:8080/mcp) | lmcp pins this in `MCP_VERSION`. aish sends the same in `initialize`; future model bumps are negotiated at connect time. |
| MCP auth | Bearer token via `Authorization: Bearer <token>` header, per-server | Analyze finding: every lmcp deployment in mfritsche's fleet (boltzmann/hertz/pve*/nc/etc.) requires Bearer auth. Phase 2 config supports `auth_token` literal and `auth_env` env-var indirection per server (mirrors `key_env` in the models registry). lmcp servers without auth (broglie/higgs LAN-only) just leave the field nil. |
| Tool-call wire format | OpenAI `tools` field on `/v1/chat/completions` body; `tool_calls` on assistant deltas; `role:"tool"` turn with `tool_call_id` for results | Standard, supported by llama.cpp and OpenRouter. Aligns with the existing `/v1/chat/completions` substrate invariant. |
| Tool namespacing | `<server-alias>.<tool-name>` for both the wire-level tool name and `:mcp tools` listing | Avoids name collisions across servers. The alias comes from the config key or the connect URL hash. |
| `CMD:` coexistence with tool-calls | Both stay live, no policy preference. Substrate invariant §3 unchanged. | Resolves Q6 (see §10). `CMD:` is the local-shell route; MCP tools are structured-API routes; they serve different purposes. Future phases (Norris, Phase 3) may prefer tools when both are available, but Phase 2 doesn't enforce. |
| Authorization default | Per-call confirm (mirrors PHASE0.md §10 `confirm_cmd` for shell) | Conservative default; user can opt into auto-approval per tool or per server via config. Resolves Q8. |
| System prompt augmentation | Hybrid: static frame in `broker.lua` system prompt + dynamic `tools` array in the request body | Tool list goes in the API field where it belongs; the system prompt only mentions that tools exist and how to use them. Per-request body cost is bounded (tools change rarely; small schemas). Resolves Q9. |
| Tool-call streaming | Streaming-from-day-one — `broker.chat_stream`'s on_delta callback widens to handle `tool_calls` deltas in addition to text deltas | Resolves Q10. Phase 1 SSE landed first, so we're not retrofitting; we just extend the parser. **Wire shape confirmed at analyze** (2026-05-12 probe vs hossenfelder): `delta.tool_calls[]` arrives indexed; id+type+function.name appear on the opening delta; `function.arguments` is a JSON-string that arrives in character-fragment chunks; finish_reason "tool_calls" closes the call. Accumulator strategy matches §5. |
| Tool-call concurrency | Sequential dispatch in Phase 2 v1 — process `tool_calls[0]` to completion, then `[1]`, etc. | Simpler error handling; tool effects often order-dependent (e.g. write-then-read). Parallel dispatch deferred (see Q20). |
| MCP server lifecycle | aish does not manage MCP server processes (parallel to PHASE0.md §12 llama.cpp rule) | Declared in config or connected by URL; aish is a client only. |

---

## 3. Module Changes

| File | State after Phase 1 | Phase 2 changes |
|---|---|---|
| `mcp.lua` | **New file** (not in PHASE0 §4 layout; this Phase amends the layout to add it) | Implement: `M.connect(url, opts) -> session` (opts: `alias`, `auth_token`, `auth_env`), `session:initialize()`, `session:list_tools() -> [{name, description, schema}]`, `session:call_tool(name, args) -> result | tool_error`, `session:close()`. JSON-RPC 2.0 over HTTP POST (`Content-Type: application/json`, `Accept: application/json`, `Authorization: Bearer <token>`). Per-session state: alias, base-url, auth, tools-cache, request-ID counter. No persistent SSE channel — POST is one-shot per RPC. |
| `safety.lua` | Stub | Implement Phase 2 surface only: `M.confirm_tool_call(tool_name, args, policy) -> bool`. Reads `config.mcp.auto_approve` (per-tool and per-server) before prompting. Norris destructive-op heuristic and HALT gate stay Phase 3. |
| `broker.lua` | Streaming `chat_stream(cfg, msgs, on_delta)` | Request body grows `tools = mcp.tools_schema()` (assembled from all connected sessions). on_delta callback widens to `on_delta(kind, payload)` where `kind ∈ {"text", "tool_call"}`; tool_call payload includes id+name+arguments-delta. `M.chat` wrapper updates to buffer both. |
| `context.lua` | turns = {{role, content}, ...} + `pending_exec_output` | New role: `"tool"`. Assistant turns may carry `tool_calls = [{id, name, arguments}]`. `to_messages()` flattens these into OpenAI-shape messages. Alternation rules: assistant-with-tool_calls is followed by N tool turns (one per call), then assistant text. |
| `repl.lua` | meta cmds + ask_ai stream loop | After ask_ai sees `tool_calls`, enter a tool-execution sub-loop: confirm-gate each call via `safety.confirm_tool_call`, dispatch via `mcp.session:call_tool`, append tool turn to context, re-issue the broker request. Loop until assistant emits text without tool_calls. New meta: `:mcp connect <url> [alias]`, `:mcp list`, `:mcp tools`, `:mcp disconnect <alias>`. |
| `renderer.lua` | streaming text + exec frame | Add `tool_call_begin(name, args)`, `tool_call_end(result, ok)`. Visual style: indented, dim, parallel to the exec frame. |
| `config.lua` | example with models/shell/context/history | Schema additions: `mcp = { servers = { alias = { url = "..." } }, auto_approve = { ["alias.tool"] = true } }`. Documented in §10 below. |
| `ffi/curl.lua` | post + post_sse | **No additions in v1** — analyze finding ruled out the long-lived SSE GET channel for lmcp. Phase 1 `M.post` (already does sync POST with response capture) is sufficient for MCP JSON-RPC. |
| `history.lua` | JSONL session log | Tool turns are logged like any other turn — `{role:"tool", tool_call_id:"...", content:"..."}`. Resume reconstructs them via `ctx:append` like user/assistant turns. |

§4 module-layout amendment: `mcp.lua` slots between `broker.lua` and
`router.lua` in the §4 table. Same commit lands the manifest amendment.

---

## 4. MCP Transport (analyze findings — lmcp v0.5.4)

lmcp implements only the **synchronous POST** flavor of the MCP
streamable-HTTP spec. Each RPC is one HTTP transaction:

```
client → server:   POST /mcp           Content-Type: application/json
                                       Accept: application/json
                                       Authorization: Bearer <token>
                                       Body: { jsonrpc:"2.0", id, method, params }
                                       Returns: { jsonrpc, id, result | error }
                                       Connection: close
```

lmcp's `GET /mcp` exists but only sends a one-shot `event: endpoint`
announcing the POST URL, then closes — there is no held-open
server→client channel. Combined with the `listChanged: false`
capability lmcp announces in `initialize`, **aish does not open a
persistent SSE channel** to lmcp servers in v1. Notifications-from-server
are out of scope here; track for v2 if a richer server appears.

### Handshake

1. `initialize` request: `{ protocolVersion: "2025-03-26", capabilities: {}, clientInfo: { name: "aish", version: "..." } }`.
2. Server response (lmcp): `{ protocolVersion: "2025-03-26", capabilities: { tools: { listChanged: false } }, serverInfo: { name, version } }`.
3. `notifications/initialized` POST (one-way; lmcp returns HTTP 202 with no body).

### Tool discovery

1. `tools/list` RPC → `{ tools: [{ name, description, inputSchema }] }`.
2. Cache per-session **for the session lifetime** — lmcp announces
   `listChanged: false`, so there's no need to refetch or listen for
   change notifications.

### Tool invocation

`tools/call` with `{ name, arguments }`. lmcp distinguishes two failure
modes:

- **Tool-handler exception** → JSON-RPC `result` with `isError: true`
  and `content: [{ type:"text", text: "Error: ..." }]`. **Model-recoverable**:
  feed it back to the model as the next `role:"tool"` turn content and
  let it react.
- **Unknown method or unknown tool** → JSON-RPC `error` with
  `code: -32601` ("Method not found" / "Tool not found"). **Transport
  level**: surface as an aish status, do not feed to model.

This split resolves Q21.

### Lifecycle

- Connect on startup (from `config.mcp.servers`) — best effort; failures
  are status-logged, don't abort aish. "Connect" here means: do the
  `initialize` round-trip + cache `tools/list` results.
- `:mcp connect <url>` adds a session at runtime; alias auto-derived
  from hostname or supplied as second arg.
- `:mcp disconnect <alias>` drops cached state. There's no long-lived
  HTTP connection to close (every RPC was already `Connection: close`).
- On aish quit, sessions are just forgotten — nothing to clean up
  server-side.

---

## 5. Tool-Call Bridge

### Broker request body (delta from Phase 1)

```json
{
  "model": "...",
  "messages": [...],
  "stream": true,
  "temperature": 0.2,
  "tools": [
    { "type":"function",
      "function": { "name":"<alias>.<tool>",
                    "description":"...",
                    "parameters": <inputSchema> } },
    ...
  ]
}
```

The `tools` array is assembled by `mcp.tools_schema()` — flattens
`tools/list` results from every connected session, namespacing each tool
as `<alias>.<name>`.

### Response handling (streaming)

llama.cpp / OpenAI deltas may include:

```json
data: {"choices":[{"delta":{"tool_calls":[{"index":0,"id":"call_…",
                "function":{"name":"alias.tool","arguments":"{\"a\":"}}]}}]}
data: {"choices":[{"delta":{"tool_calls":[{"index":0,
                "function":{"arguments":"1}"}}]}}]}
data: {"choices":[{"finish_reason":"tool_calls",...}]}
```

`broker.chat_stream` accumulates tool-call deltas keyed by `index`; the
`arguments` field is a JSON-string that arrives chunked and is concatenated.
On `finish_reason: tool_calls`, the accumulated calls are emitted to
on_delta as `kind="tool_call"` with full payloads.

### Re-injection into context

```lua
-- After tool execution
ctx:append({
  role = "assistant",
  content = "",                -- or any model-emitted text
  tool_calls = { {id="call_…", name="alias.tool", arguments=<json-string>} },
})
ctx:append({
  role = "tool",
  tool_call_id = "call_…",
  content = <tool-result-text>,
})
```

`to_messages()` renders both shapes for the next broker request. The
strict-alternation issue from PHASE0.md §6 (mistral-nemo Jinja) is
handled differently here — tool turns ARE expected to follow assistant
tool_calls per the OpenAI chat-template convention. If a model's
template still rejects this shape, fall back to the `[tool: X]` prefix
strategy used for exec output (Q18 below).

### Re-issuing the broker request

After tool turns are appended, the broker is called again with the
extended messages array. The model may emit more `tool_calls`, more
text, or both. Loop until the response has no `tool_calls` (i.e. a
plain text assistant turn).

Budget: a max-tool-call-depth setting (default 8) prevents runaway loops.
Hit-cap surfaces as a status: `[aish] tool-call depth limit reached`.

---

## 6. Authorization (safety.lua Phase 2 surface)

```lua
-- safety.confirm_tool_call(tool_name, args_table, config) -> bool
function M.confirm_tool_call(name, args, cfg)
    local policy = cfg.mcp and cfg.mcp.auto_approve or {}
    if policy[name] then return true end
    -- Per-server prefix check: "alias.*" entries
    local alias = name:match("^([^.]+)%.")
    if alias and policy[alias .. ".*"] then return true end
    -- Otherwise prompt
    local pretty = name .. "(" .. (#args > 0 and "..." or "") .. ")"
    local ans = rl.readline(("call '%s'? [y/N] "):format(pretty)) or ""
    return ans:lower():sub(1,1) == "y"
end
```

Config schema (analyze-revised — Bearer auth fields added):

```lua
mcp = {
    servers = {
        boltzmann = {
            url       = "http://boltzmann.fritz.box:8080/mcp",
            auth_env  = "BOLTZMANN_MCP_TOKEN",  -- read from env at startup
        },
        broglie = {
            url = "http://broglie.fritz.box:8080/mcp",
            -- no auth (LAN-only deployment)
        },
        nc = {
            url        = "https://nc.reauktion.de:8080/mcp",
            auth_token = "literal-token-if-not-using-env",  -- alternative
        },
    },
    auto_approve = {
        ["boltzmann.read_file"] = true,    -- specific tool
        ["broglie.*"]           = true,    -- whole server
    },
    max_tool_depth = 8,
}
```

Auth precedence per server: `auth_token` literal > `auth_env` indirection
> nil (no Authorization header sent). Mirrors PHASE0 §10's `key_env`
convention for cloud model API keys.

Norris mode (Phase 3) will extend this: when autonomous, the destructive-op
heuristic decides; for non-destructive tools, auto_approve. Outside scope here.

---

## 7. Meta Commands (Phase 2 additions)

| Command | Action |
|---|---|
| `:mcp connect <url> [<alias>]` | Open a session; perform initialize + tools/list; add to active set |
| `:mcp disconnect <alias>` | Close one session |
| `:mcp list` | Show connected sessions (alias, url, tool count, status) |
| `:mcp tools` | List tools across all sessions (`alias.name` — short description) |
| `:mcp tool <alias.name>` | Show one tool's full inputSchema (debug aid) |

Existing `:help` updated to list these.

---

## 8. System Prompt Augmentation

`broker.lua`'s default system prompt grows by ~4 lines:

```
You may have access to MCP tools — they appear in this request's `tools`
field. Call a tool by emitting a tool_call; the result will be supplied
in the next turn. Use tools for structured operations (file reads,
queries, etc.) and `CMD:` lines for local shell commands. Prefer tools
when available; fall back to `CMD:` for anything not exposed as a tool.
```

The actual tool list is in the `tools` request-body field, not the
prompt. This avoids per-turn token bloat for the full schema.

§3 substrate invariants are unchanged. The `CMD:` extraction marker stays
the local-shell route; tools are the additive structured route.

---

## 9. Migration from Phase 1

User-visible changes:
- New `:mcp …` meta commands when MCP servers are configured or
  connected at runtime.
- Assistant responses may now invoke tools — user sees a confirm prompt
  (similar to `CMD:` execution gate) followed by an indented tool-call
  frame with the result.
- `CMD:` lines still work exactly as before for shell.

Substrate (PHASE0.md §3) invariants: unchanged. Module layout (§4)
amended to add `mcp.lua`; that amendment ships in the manifest commit.

`config.lua`: existing configs without an `mcp` section continue to work
— no MCP servers means no tools sent in the broker request body, no
auth checks, no behavior change.

---

## 10. Out of Scope (Phase 2)

Per PHASE0.md §11, these belong elsewhere:
- Chuck Norris autonomous mode (Phase 3) — even though tool-calls
  enable richer autonomy, the *autonomous policy* is Phase 3's.
- Destructive-op heuristic in safety.lua (Phase 3) — Phase 2 only
  implements the per-call confirm-prompt surface.
- `memory.jsonl` summarization across sessions (Phase 4).
- Multi-model routing / cloud fallback (Phase 5).
- Tree-sitter syntax highlighting (Phase 6).

Specifically out of Phase 2 scope despite proximity:
- Stdio-transport MCP servers (Q17 below).
- Parallel tool-call dispatch (Q20).
- MCP `resources/list` and `prompts/list` capabilities — Phase 2
  v1 only implements `tools/*`. Resources/prompts deferred (probably
  Phase 4 alongside memory).
- Server-sent `notifications/progress` for long-running tool calls —
  ignored in v1; status surface comes later.

---

## 11. Open Questions

| # | Question | Impact | Resolve by |
|---|---|---|---|
| Q17 | ~~MCP transport abstraction: stdio vs HTTP+SSE~~ | mcp.lua API shape | **Resolved at analyze.** Hard-code POST-only HTTP for v1. lmcp doesn't use the long-lived SSE channel and `listChanged: false` removes any v1 need for it. Stdio transport tracked as Phase 2.1 / out-of-scope here. |
| Q18 | Tool-result re-injection: standard OpenAI `role:"tool"` turn, or `[tool: X]` prefix to next user turn (matching the §6 exec-output pattern)? | context.lua + broker.lua | **Partly resolved.** Live probe (2026-05-12, hossenfelder) shows `role:"tool"` accepted by the proxy + the loaded model (qwen2.5-coder-1.5b). Mistral-nemo-specific template testing is **blocked** by the hossenfelder proxy routing all `model` field values to the loaded fast model — see open-end below. Default v1 path: `role:"tool"` (standard); fallback to `[tool: X]` prefix is plumbed but unused unless a strict template rejects it during Phase 7 verify. |
| Q19 | Large tool-result payloads: pass-through, truncate at N chars, or summarize via fast model? | context.lua + executor of tool-result | Phase 2 (plan); Phase 4 may refine with memory.jsonl |
| Q20 | Parallel `tool_calls`: sequential v1 is safe; spec allows parallel. Move to parallel when both calls are read-only? | mcp.lua dispatch | Phase 2 (verify) — track for v2 |
| Q21 | ~~MCP error mapping~~ | mcp.lua + broker.lua | **Resolved at analyze.** lmcp distinguishes: `result.isError=true` (handler exception, model-recoverable, feed back as tool turn content) vs JSON-RPC `error` (unknown method/tool, transport-level, surface as aish status). See §4. |
| Q22 | aish's own command surface as an MCP server | scope expansion | **Out of Phase 2.** Parked for Phase 4+ if interest stays. |

Open-end carried forward to Phase 7 (verify):
- **Hossenfelder proxy `model`-field bug** (separate from aish): the proxy at `:8082` routes all requests to the loaded fast model regardless of the request's `model` field — chunks return `"model":"qwen2.5-coder-1.5b-q4_k_m.gguf"` even when `mistral-nemo-12b-instruct` was asked for. This **blocks live-verification of mistral-nemo's chat-template tool-role behavior**. Fix lives in boltzmann (parallel to the SSE-buffering bug tracked at [aish#15](https://git.reauktion.de/marfrit/aish/issues/15)). Phase 7 needs the proxy fix to fully close Q18.

Resolved at formulate (above in §2 table):
- Q6 (CMD: vs tools coexistence) — both, no policy preference, substrate unchanged.
- Q7 (MCP discovery) — both, config-declared default + runtime `:mcp connect`.
- Q8 (authorization) — per-call confirm default, per-tool/per-server `auto_approve` policy.
- Q9 (system-prompt augmentation) — hybrid: static frame + dynamic `tools` body field.
- Q10 (tool-call streaming) — streaming-from-day-one on top of Phase 1 SSE.

Resolved at analyze (2026-05-12, live probes vs lmcp v0.5.4 + hossenfelder):
- Q17 (transport abstraction) — POST-only, no SSE channel needed for lmcp.
- Q21 (error mapping) — isError vs JSON-RPC error split per §4.

---

*End of Phase 2 Manifest — aish*