aish/docs/PHASE7.md

# aish — Phase 7 Manifest

**Project:** aish — AI-augmented conversational shell
**Document:** Phase 7 Requirements, Architecture & Design Decisions
**Status:** Formulate (pre-analyze)
**Date:** 2026-05-16

PHASE0 is the locked substrate; PHASE1-6 are layered on top. This manifest
specifies what Phase 7 adds — **cost / usage observability**: the ability
to know, mid-session, how many tokens you've spent and how much money the
paid-cloud calls have cost.

PHASE0 §11 originally listed phases only through 6; this commit amends
§11 to add Phase 7.

---

## 1. Scope of Phase 7

Four pillars:

1. **Usage capture in broker** — `broker.chat_stream` extracts the
   provider's `usage` block (and `cost` where present) from the response
   stream. Surfaces it to the caller via a new `on_delta("usage", ...)`
   kind. The existing `broker.chat` buffering wrapper exposes it as a
   second return value `(text, usage)`. Backward-compatible: callers
   that don't handle the new kind / second value simply ignore it.

2. **Per-session accumulator on `ctx`** — running totals per-model AND
   per-call-category (main / delegate / summarize / probe) accumulate on
   `ctx.usage_totals`. No persistence across sessions in v1 (Q-C2
   defers cross-session); the session-log JSONL files DO carry per-turn
   usage so historical analysis is possible after the fact.

3. **`:cost` meta** — a `:cost` reporter that shows the current session
   totals, with optional `:cost detail` for the per-model + per-category
   breakdown. Zero broker calls (purely local read of `ctx.usage_totals`).

4. **Optional warning thresholds** — `cfg.cost.warn_at_dollars` and
   `cfg.cost.warn_at_tokens` emit a status the first time the running
   total crosses the configured threshold. Default off (no warnings
   without config). Useful when cloud presets are configured and you
   want a "you've spent $1 this session" nudge before runaway cost.

**Phase 7 is done when:**

- `broker.chat_stream` exposes usage via the new `on_delta("usage", ...)`
  callback kind; `broker.chat` returns `(text, usage)`. Backward compat
  preserved (no existing caller breaks).
- After a session with mixed local + cloud calls, `:cost` prints a
  total like:
  ```
  [aish] session usage: 24 turns, prompt=12,450 / completion=3,210 tokens
                                  cost=$0.0234 (cloud only; local: 0)
  ```
- `:cost detail` breaks down by model + category:
  ```
  fast    main: 14 turns, 8200/2100 tokens
  cloud   main: 8 turns, 3850/980 tokens, $0.0180
  cloud   delegate: 1 turn, 250/80 tokens, $0.0012
  cloud   probe: 1 turn, 150/30 tokens, $0.0042
  ```
- Session JSONL gains a `usage` field on assistant turns (when the
  broker returned one).
- With `cfg.cost.warn_at_dollars = 0.50` set, crossing $0.50 cumulative
  emits exactly one status line.
- Existing configs without `cfg.cost` behave exactly like Phase 6
  (Phase 6 regression coverage).

---

## 2. Technology Decisions (delta from Phase 6)

| Decision | Choice | Rationale |
|---|---|---|
| Where to extract usage | In `broker.chat_stream` event loop, looking at each SSE event's `usage` field on the final chunk | The OpenAI streaming spec puts `usage` on the FINAL chunk when `stream_options: { include_usage: true }` is in the request body. The Anthropic-via-Bedrock path through OpenRouter respects this; need to verify (baseline). |
| New on_delta kind | `on_delta("usage", { prompt_tokens, completion_tokens, total_tokens, cost?, model?, native_finish_reason? })` | Mirrors the existing `("text", chunk)` / `("tool_call", call)` shape. Callers ignore unknown kinds; backward-compatible. |
| Where to enable usage on the wire | `opts.include_usage = true` (default `true`) sets `stream_options.include_usage = true` in the outbound request body | Off-switch for hosts that reject `stream_options`. Defaults on; baseline probe confirms current broker tolerates it. |
| Accumulator location | `ctx.usage_totals[model_name][category]` table | ctx is per-conversation; matches the `:reset`-survives-or-not rules already in place. |
| Categories | `"main"` (ask_ai), `"delegate"`, `"summarize"`, `"memory_summarize"`, `"probe"`, `"norris"` | One-tag-per-call-site. Tagged at the caller site (caller passes `opts.category` to `broker.chat_stream`). |
| Cost extraction | `usage.cost` (OpenRouter convention; dollars as a number) plus `usage.cost_details.upstream_inference_cost` (more detailed). For Anthropic/Bedrock the cost arrives in dollars on `usage.cost`. For pure local llama.cpp: no `cost` field — record 0. | Single field name across all observed providers (per baseline B7 — to be confirmed). |
| Cost precision | Store as `number` (Lua double = 53-bit mantissa, ~15 decimal digits — plenty for sub-cent precision) | No floating-point cumulative-error concerns at this scale. |
| Warning trigger | First crossing of either threshold emits a single status: `[aish] session cost $X.XXXX has crossed warn_at_dollars=$Y.YYYY`. Crossed-flag stored on ctx; reset only on session end / `:cost reset`. | One-shot to avoid spamming. |
| `:reset` interaction | `:reset` does NOT clear `ctx.usage_totals` (parity with `memory_items`/`project`) — the user reset their conversation, not their cost tracking. `:cost reset` is the explicit reset verb. | Matches R8 invariant from Phase 6. |
| Session-log persistence | Assistant turn entries gain an optional `usage` field when broker returned one. `history.lua` log_turn writes it through verbatim. | Per-turn granularity preserved for after-the-fact analysis. No new file. |

---

## 3. Module Changes

| File | State after Phase 6 | Phase 7 changes |
|---|---|---|
| `broker.lua` | `chat_stream(cfg, msgs, on_delta, opts)` with text + tool_call kinds; `chat` returns text | Extract usage from final SSE chunk; emit `on_delta("usage", payload)`; `chat` returns `(text, usage)`. New `opts.include_usage` (default true); new `opts.category` (passed through as a tag in the usage payload). |
| `context.lua` | system prompt + turns + memory + project + summary | Add `self.usage_totals` (table) + `self.cost_warn_fired` (bool). New helpers: `Context:add_usage(model, category, usage)`, `Context:total_cost()`, `Context:total_tokens()`. `Context:reset` does NOT clear `usage_totals` (parity with memory_items / project per R8). |
| `repl.lua` | ask_ai + delegate + summarize callbacks + Norris helpers | Wire `opts.category` at each broker call site (main / delegate / summarize / memory_summarize). Wire `on_delta("usage", ...)` -> `ctx:add_usage(...)`. New `:cost` and `:cost detail` / `:cost reset` metas. Cost-warn check after each `add_usage` call. |
| `safety.lua` | norris_step + is_destructive | Pass `opts.category = "norris"` (for the main chat_stream call) and `"probe"` (for the is_destructive LLM probe). Surfaces probe-cost in the breakdown — useful since `safety.llm_model = "cloud"` is the recommended setting. |
| `history.lua` | session.log_turn appends JSONL entries | log_turn already takes turn opaquely; assistant turns will carry `usage` if present and it'll serialize via dkjson. No code change unless filter desired. |
| `config.lua` | example blocks for mcp/safety/memory/routing/secrets/hooks/project | Add commented-out `cost = { warn_at_dollars, warn_at_tokens }` block. |
| `docs/PHASE0.md` | §11 lists phases 0-6 | **Amendment**: add Phase 7 row to §11. |

No new module files.

---

## 4. Pillar 1 — Usage capture in broker

### SSE shape (provider-by-provider — confirm in baseline)

For OpenAI-compatible streams with `stream_options: { include_usage: true }`:

```json
data: {"id":"...","choices":[{"index":0,"delta":{"content":"Hi"}, ...}]}
data: {"id":"...","choices":[{"index":0,"delta":{}, "finish_reason":"stop"}]}
data: {"id":"...","choices":[],"usage":{"prompt_tokens":15,"completion_tokens":3,"total_tokens":18,"cost":0.00004,"cost_details":{...}}}
data: [DONE]
```

The final usage event arrives AFTER `finish_reason` but BEFORE `[DONE]`.
`choices` is empty `[]` on the usage event.

For non-streaming `chat`: usage is in the response body at the top level.
broker.chat is a wrapper around chat_stream, so it inherits the on_delta
path.

For local llama.cpp via hossenfelder: usage may or may not be present
depending on the proxy's version. Treat absence as zero-cost / unknown.

### Extraction algorithm

```lua
local final_usage = nil

local function on_event(data)
    ...
    if doc.usage then
        -- Provider sent usage; capture for emission after the stream.
        final_usage = {
            prompt_tokens     = doc.usage.prompt_tokens or 0,
            completion_tokens = doc.usage.completion_tokens or 0,
            total_tokens      = doc.usage.total_tokens or 0,
            cost              = doc.usage.cost,   -- nil for local
            model             = doc.model or model_cfg.model,
        }
        -- Don't emit yet — the [DONE] event marks stream end; emit
        -- once we exit the curl.post_sse loop so the caller sees
        -- usage as the LAST event in the stream order.
    end
    -- ... existing text + tool_call handling ...
end

-- After curl.post_sse returns (stream complete):
if final_usage then on_delta("usage", final_usage) end
```

### Outbound include_usage

```lua
local body_table = { model = ..., messages = ..., stream = true }
if opts.include_usage ~= false then
    body_table.stream_options = { include_usage = true }
end
```

Risk: some providers reject unrecognized fields. Baseline check; if any
host throws on `stream_options`, the per-model opt-out is one line.

### Category tagging

`opts.category` is a string set by the caller. broker echoes it into the
emitted usage payload so the accumulator knows what to credit. Default
category if absent: `"main"`.

---

## 5. Pillar 2 — Accumulator on ctx

### Shape

```lua
ctx.usage_totals = {
    -- [model_name] = { [category] = { prompt = N, completion = N,
    --                                 calls = N, cost = N } }
    fast = {
        main      = { prompt = 1234, completion = 567, calls = 14, cost = 0   },
    },
    cloud = {
        main      = { prompt = 3850, completion = 980, calls = 8,  cost = 0.0180 },
        delegate  = { prompt = 250,  completion = 80,  calls = 1,  cost = 0.0012 },
        probe     = { prompt = 150,  completion = 30,  calls = 1,  cost = 0.0042 },
    },
}
ctx.cost_warn_fired = false
```

### add_usage

```lua
function Context:add_usage(model, category, u)
    model    = model    or "?"
    category = category or "main"
    self.usage_totals = self.usage_totals or {}
    local m = self.usage_totals[model] or {}
    local c = m[category] or { prompt = 0, completion = 0, calls = 0, cost = 0 }
    c.prompt     = c.prompt     + (u.prompt_tokens or 0)
    c.completion = c.completion + (u.completion_tokens or 0)
    c.calls      = c.calls      + 1
    c.cost       = c.cost       + (u.cost or 0)
    m[category] = c
    self.usage_totals[model] = m
end

function Context:total_cost()
    local total = 0
    for _, m in pairs(self.usage_totals or {}) do
        for _, c in pairs(m) do total = total + c.cost end
    end
    return total
end

function Context:total_tokens()
    local p, comp = 0, 0
    for _, m in pairs(self.usage_totals or {}) do
        for _, c in pairs(m) do
            p    = p    + c.prompt
            comp = comp + c.completion
        end
    end
    return p, comp
end
```

### Reset semantics

`Context:reset()` deliberately does NOT clear `usage_totals` —
matches R8 invariant from Phase 6 (`:reset` clears `turns`,
`pending_exec_output`, `summary`; preserves `memory_items`, `project`,
and now `usage_totals`). The user reset their conversation, not their
cost meter. `:cost reset` is the explicit reset verb for the meter.

---

## 6. Pillar 3 — `:cost` meta

```
:cost                       summary line
:cost detail                per-model + per-category breakdown
:cost reset                 zero out ctx.usage_totals + cost_warn_fired
```

Summary format:

```
[aish] session usage: 24 calls, prompt=12,450 / completion=3,210 tokens
                       cost=$0.0234 (cloud only; local: 0)
```

Detail format (sorted by total cost desc, then by model):

```
[aish] session usage detail:
  cloud     main      8 calls,  3,850 / 980 tokens,   $0.0180
  cloud     delegate  1 call,     250 / 80  tokens,   $0.0012
  cloud     probe     1 call,     150 / 30  tokens,   $0.0042
  fast      main     14 calls,  8,200 / 2,100 tokens, $0     (local)
```

Implementation: pure Lua iteration over `ctx.usage_totals`; no broker
calls. Sorting uses `table.sort` on a flattened list.

---

## 7. Pillar 4 — Warning thresholds

Config:

```lua
cost = {
    warn_at_dollars = 0.50,    -- emit once when cumulative cost crosses
    warn_at_tokens  = 100000,  -- emit once when cumulative tokens crosses
}
```

After every `ctx:add_usage`, check:

```lua
if config.cost and not ctx.cost_warn_fired then
    local cost = ctx:total_cost()
    if config.cost.warn_at_dollars and cost >= config.cost.warn_at_dollars then
        renderer.status(("session cost $%.4f has crossed warn_at_dollars=$%.4f")
                        :format(cost, config.cost.warn_at_dollars))
        ctx.cost_warn_fired = true
    end
    -- (similar for warn_at_tokens; share the flag or use two)
end
```

One-shot per session. `:cost reset` clears the flag.

---

## 8. UX Surface Summary

| Meta | Behavior |
|---|---|
| `:cost` | One-line summary: calls / tokens / cost |
| `:cost detail` | Per-model + per-category breakdown |
| `:cost reset` | Zero out totals + clear warn-fired flag |

| Config | Default | Effect |
|---|---|---|
| `cfg.cost.warn_at_dollars` | nil | Status when cumulative cost first crosses this dollar amount |
| `cfg.cost.warn_at_tokens` | nil | Status when cumulative total tokens first crosses |
| (broker `opts.include_usage`) | true | Adds `stream_options.include_usage = true` to outbound request |

---

## 9. Out of Scope (Phase 7)

- **Cross-session cost persistence** — Q-C2 defers `<history.dir>/cost.jsonl`
  rollup; v1 is session-only. Per-turn usage IS in the session JSONL for
  after-the-fact aggregation if anyone wants to script it.
- **Per-model rate limiting / cost caps that REFUSE the call** — v1 only
  warns. A future phase could add a hard cap that aborts before the
  broker call.
- **Pricing-table fallback for local models** — if a local model doesn't
  emit `usage.cost`, we record 0. Estimating cost from token count + a
  static pricing table is a future polish (most users won't care about
  local "cost" anyway — local is free).
- **Pretty token-bandwidth charts / sparklines** — out of scope; the
  detail breakdown is text-only.
- **Estimated cost for future turns** — no preflight cost prediction.
- **MCP tool-call usage** — MCP servers don't expose token usage;
  broker calls invoked DURING MCP tool dispatch ARE captured (because
  they go through the same path), but the MCP tool call itself isn't.

---

## 10. Risks

| Risk | Mitigation |
|---|---|
| Some providers reject `stream_options` -> SSE errors at the top of the stream | `opts.include_usage = false` opt-out per call site; baseline-time probe of the actual hossenfelder broker behavior |
| OpenRouter `cost` field shape varies between providers (Bedrock vs. Baidu vs. Together vs. ...) | Capture `usage.cost` as-is (number); document that the same provider must be used for cross-call comparison |
| Local llama.cpp returns no `cost` -> displayed `$0` could mislead user "is this REALLY free?" | `:cost detail` annotates local lines with `(local)` literal; summary says `cost=$X (cloud only; local: 0)` |
| `ctx.usage_totals` grows unboundedly with new model names mid-session | Bounded by `#models in config` × `#categories` — small constants. No mitigation needed. |
| Warn threshold fires once and never again for a long-running session that crosses 2x / 10x the threshold | Acceptable for v1; user can `:cost reset` to re-arm. Future polish: warn at each Nx multiple. |

---

## 11. Open Questions (Phase 7)

| # | Question | Impact | Resolution target |
|---|---|---|---|
| Q-C1 | What to do when a provider doesn't emit `usage` (local llama.cpp, some misconfigured proxies)? Record zero / silently skip / estimate via char/4? | Accumulator entries for those models | Analyze (probe what hossenfelder actually returns per model class) |
| Q-C2 | Should `<history.dir>/cost.jsonl` accumulate cross-session totals? `:cost --all-time` reporter? | New file + persistence layer | Defer to follow-up phase (v1 = session only) |
| Q-C3 | Categories vs free-form tags — should `opts.category` be free-form (caller decides) or validated against a closed set? | Predictability of `:cost detail` output | Analyze |
| Q-C4 | Does the hossenfelder broker forward `stream_options` to all backends? Some backends may strip it. | include_usage default | Baseline (real probe) |
| Q-C5 | Should `cfg.cost.warn_at_dollars` trigger on the FIRST broker call that crosses, or on the NEXT one (so user sees the call complete before the warn)? | UX detail | Analyze |
| Q-C6 | When `:reset` is called, should `cost_warn_fired` be cleared too (so the next warn-cross fires again)? Or only clear via `:cost reset`? | Reset surface area | Analyze |

---

## 12. Phase 7 → Phase 8+ Out-of-band

Candidate follow-ups (non-binding):

- **Phase 8**: cross-session cost persistence (Q-C2 deferral), with
  optional cost dashboards / weekly rollup reporter.
- **Hard rate limits / cost caps that REFUSE the call** — an extension
  of the warn surface that promotes warnings into preflight enforcement.
- **Better tokenization** (Q1 deferred-from-Phase-3): replace the char/4
  heuristic on `Context:estimate_tokens()` with model `/tokenize` calls.
  Indirectly improves accuracy of any future "preflight cost predictor".

Phase 7 itself is self-contained — no upstream dependencies.