Module transform_http 

The typed-transform write surface (#837 piece A): POST /v1/transform, and the shared apply_transform that lex ws transform also calls. The typed-transform write surface (#837 piece A).

POST /v1/transform lets an agent harness make a typed edit — one of #280’s four transforms — straight through the op log, instead of editing text and running lex publish. The same code path backs lex ws transform (an embedded on-disk store, no server): [apply_transform] is the single function both call, so the two cannot diverge.

Request

{
  "branch": "main",                       // REQUIRED. Never the server's global current branch.
  "intent": {                             // optional; absent => explicitly unattributed (#970)
    "prompt": "why", "model": "provider/name", "session": "s-1", "issue_id": "..."
  },
  "transform": { "kind": "...", ... }     // kind-specific, below
}

kind	params	ops emitted
replace_match_arm	from_stage_id, match_node, arm_index, new_body (CExpr)	ReplaceMatchArm
rename_local	from_stage_id, let_node, new_name	RenameLocal
inline_let	from_stage_id, let_node	InlineLet
extract_function	from_stage_id, expr_node, spec {name, type_params?, params, return_type, effects?}	AddFunction + ModifyBody

from_stage_id must be the stage the branch head currently binds to the function’s signature (stale ids are refused with 409). This is the same payload lex repair --apply --transform takes.

Response (200)

{ ok, branch, kind, op_id, op_ids, prev_head, new_head, new_stage_id, extracted?, intent: { intent_id, session_id, unattributed } } — op_id is the last op emitted (the new head); op_ids lists all of them (two for extract_function); extracted is { sig_id, stage_id } of the new function.

Errors

400 malformed body / missing branch / blank intent.prompt; 404 unknown branch or stage; 409 stale from_stage_id, no-op transform, or a function not on the branch head; 422 the transform did not apply (unknown node, wrong node kind, …) or the result fails the write-time gate — with the diagnostics under detail.errors. Every refusal leaves the branch head unchanged and writes no op and no intent.

Intent

Attribution follows lex publish (#970): an absent intent is recorded as an explicitly unattributed intent, never as none. A session that is not supplied defaults, like publish’s cli-<pid>-<epoch>, to a per-process http-<pid>-<epoch> — so an omitted session makes the OpId non-reproducible; pin session for a deterministic OpId. The resolved ids are echoed in the response.

Structs

Applied

What a successful transform landed.

ExtractSpec

Wire form of lex_ast::ExtractFnSpec.

IntentSpec

The wire form of an intent: every field optional.

Enums

TransformSpec

A typed transform request; the JSON shape matches lex repair --transform.

Constants

UNATTRIBUTED_PROMPT

The prompt recorded when a write declares none (#970). Deliberately not a plausible-looking prompt: it must be impossible to mistake a synthesized intent for one a caller supplied, and it is a fixed string so it is exactly matchable (lex recall --predicate lists every unattributed op).

Functions

apply_transform

Apply spec to branch through the store’s gated apply path, attributing every op to intent. The one function POST /v1/transform and lex ws transform share.

build_intent

Build (not record) the Intent for a write from its optional parts. The one implementation lex publish, lex ws transform and the HTTP write endpoints share, so an unattributed write looks the same whichever door it came through. default_session is only called when session is None.

default_http_session

The session id for an HTTP write that gave none: per-process, like publish’s cli-<pid>-<epoch>, and for the same reason (a constant default would collapse every anonymous write into one bogus session).

split_model_ref

provider/name → (provider, name). A bare name is attributed to provider cli; None → ("cli", "unknown"). The model ref feeds the content- addressed IntentId, so the default must be stable, not empty.