feat: generate into a pending message, at most once by robelest · Pull Request #444 · convex/agent

robelest · 2026-10-31T01:25:35Z

Draft for discussion of #150 and #168. Not for merging yet.

pendingMessageId lets a generation fill a pending message the caller saved, at most once, with its stream linked to that message. Claims live in a new claims table. example/convex/batch uses it for batch answers.

The first 5 commits are an unpushed rework of fix(streaming): drive step saves and failures from what the AI SDK does #397, which this depends on.
Known gap: if an action dies after an approved tool ran but before its result was saved, the takeover reruns the tool.
Known gap: the batch example's replay depends on the claimed generation's context.
Open questions are in PRIMITIVES.md.

…p it, and provider errors reach fullStream (#388, #428)

…tops the stream keeps earlier steps (#388)

…ailed step save's error (#388)

…he result resolves (#388, #428) onStepEnd only holds the step. prepareStep saves it with the next pending message in one mutation, and a transform after the user's saves the last one before `finish` reaches the caller. A provider error is forwarded to onError and ends the step as failed instead of aborting the stream.

…ut fails only its own (#150, #168)

…streams to it (#150, #168) A pendingMessageId option claims the message before the model is called. A second claim while one runs, or once the answer is saved, throws AlreadyClaimedError; a failed or lapsed claim continues the answer in a new pending message. Streams record the pending message they write to, step saves move the link, a timeout fails only that message, and recovery reads only its streams.

… save (review)

…, and batch saves retry without replaying (review)

…ool step, and an approval continuation don't break the claim (review)

…ration's last save, and recover a lapsed attempt in the takeover (review)

… reference is found and saved (review)

…ing it, and find a batch whose reference was lost (review)

…r key

…ted (review)

…submitting (review)

…keeps its prompt (review)

…ps its prompt (review)

…a lost batch isn't confused with a newer one (review)

… lost batch is found exactly (review)

…review)

…search open (review)

…nd two batches for one prompt (review)

…m, not by stepOrder (review)

…saved, and check failed batches when finding a lost one (review)

…ved nothing (review)

…text (review)

…tion streamed (review)

…a stream's link follow its pending message (review)

…newer prompt (review)

…sage's order (review)

pkg-pr-new · 2026-10-31T01:27:01Z

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npm i https://pkg.pr.new/@convex-dev/agent@444

commit: 29462bf

robelest added 30 commits October 30, 2026 21:23

test: every step is saved before its result, failures and retries sto…

9cd07c7

…p it, and provider errors reach fullStream (#388, #428)

test: a failed answer save rejects the result, and a transform that s…

7a300ed

…tops the stream keeps earlier steps (#388)

test: a rejected request fails the generation, and an abort keeps a f…

59740aa

…ailed step save's error (#388)

test: a transform that throws at the end keeps the answer (#388)

85ca36c

chore(example): bring the batch recipe over from the batch spike

74f7e84

test: generate into an owned pending message once, and a stream timeo…

66b986b

…ut fails only its own (#150, #168)

refactor(example): batch on pending answers, saved once (#150)

3b9ec32

test: a lapsed claim's recovery, a foreign thread, and a failed batch…

cd19e27

… save (review)

fix: the latest claim is the current attempt, claims check the thread…

0b459a5

…, and batch saves retry without replaying (review)

docs: pending-message primitives design note

1e295dd

test: a failed generation's saved step, a lapsed attempt's streamed t…

315a08d

…ool step, and an approval continuation don't break the claim (review)

fix: keep claims in their own table, answered only by a finished gene…

4a83bdd

…ration's last save, and recover a lapsed attempt in the takeover (review)

test(example): a batch whose submitting action died before saving its…

55aacd8

… reference is found and saved (review)

fix(example): save a batch's items and pending answers before submitt…

f355d57

…ing it, and find a batch whose reference was lost (review)

test: a claim's current pending message can't be claimed under anothe…

0885d8e

…r key

fix: refuse to claim a message another claim saves into

6449078

docs: claims live in their own table

7649c6d

test(example): the first poll is scheduled before the batch is submit…

4c6244a

…ted (review)

fix(example): schedule the first poll with the batch's items, before …

05584e8

…submitting (review)

test: a recovered message fences its generation, and a recovered key …

8052223

…keeps its prompt (review)

fix: a saved pending message refuses further saves, and the claim kee…

2d8333d

…ps its prompt (review)

docs: the claim keeps its prompt, and saved pending messages are fenced

aa49a0b

test: approved tools run once when the request after them fails, and …

2cdea58

…a lost batch isn't confused with a newer one (review)

fix: save approved tools' results before the first request (review)

bbaa9f8

fix(example): batch requests are keyed by their pending answers, so a…

0a67971

… lost batch is found exactly (review)

docs: approved tool results and batch request ids

aafe1c3

test(example): a lost batch survives a failed lookup of its results (…

fa09066

…review)

fix(example): a batch that can't be checked yet keeps a lost batch's …

5bef3bb

…search open (review)

robelest added 16 commits October 30, 2026 21:23

docs: tools in flight when an action dies

09eb465

test: takeover recovery with a shared order, an expired lost batch, a…

bfd9fc0

…nd two batches for one prompt (review)

fix: recovery skips the messages a stream saved, counted on the strea…

ecfc01f

…m, not by stepOrder (review)

fix(example): replay a batch result only into an answer with nothing …

5b63553

…saved, and check failed batches when finding a lost one (review)

docs: stream save counter and batch replay rule

dafb45a

test(example): a batched tool call runs once after an attempt that sa…

b30a693

…ved nothing (review)

fix(example): decide a batch replay from the claimed generation's con…

9b9fa3c

…text (review)

docs: batch replay follows the claimed context

9873939

test: a takeover keeps a later tool step a streamed approval continua…

59d2e71

…tion streamed (review)

fix: recover a streamed approval continuation's later steps, and let …

e140f53

…a stream's link follow its pending message (review)

docs: stream links and counts

2777575

docs: batch replay and context handlers

596afc7

test: a takeover keeps recovered steps at the prompt's order after a …

43b6aa2

…newer prompt (review)

fix: a save into a pending message without a prompt stays at that mes…

538c49f

…sage's order (review)

docs: recovered steps stay at their order

a286afc

docs: the streamed approved-output window

29462bf

robelest requested a review from ianmacartney October 31, 2026 01:25

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feat: generate into a pending message, at most once - #444

feat: generate into a pending message, at most once#444
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