fix: add persistent cost to prevent under-reporting spent value by IdrisGit · Pull Request #7763 · anomalyco/opencode

IdrisGit · 2026-01-11T08:19:33Z

What does this PR do?

This PR adds a persistent cost field to sessions to fix incorrect cost reporting in the sidebar when sessions exceed 100 messages. Previously, cost was calculated from the last 100 messages only, causing under-reporting for long sessions.

Key changes:

Added cost field to Session schema
Sessions now accumulate cost incrementally when assistant messages complete
Sidebar reads cost directly from session metadata instead of summing messages
Forked sessions inherit parent's accumulated cost
Added startup migration to backfill existing sessions

How did you verify your code works?

Verified with before/after testing on the same long session:

v1.1.12: Sidebar showed $0.12 (incorrect - last 100 messages only)
Local build: Sidebar shows $1.61 (correct - accumulated total cost)
Used local build to work on an issue in the same session, cost is being accumulated correctly.

OpenCode v1.1.12

OpenCode local

Fixes #7767 #6989

…iving from the messages array max 100 messages are kept in the store/memory which leads to misreporting of the actual spend value

github-actions · 2026-01-11T08:19:48Z

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

Open an issue describing the bug/feature (if one doesn't exist)
Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

github-actions · 2026-01-11T08:20:07Z

The following comment was made by an LLM, it may be inaccurate:

No duplicate PRs found

rekram1-node · 2026-01-14T17:07:32Z

packages/opencode/src/cli/cmd/tui/routes/session/sidebar.tsx


  const cost = createMemo(() => {
-    const total = messages().reduce((sum, x) => sum + (x.role === "assistant" ? x.cost : 0), 0)
+    const total = session().cost ?? 0


you would want to fallback to the messages cost right cause otherwise opening old sessions would show 0

It should be handled by the migration script for old sessions as well, but yeah it makes more sense to fallback to the old method instead of defaulting to zero. updated.

rekram1-node · 2026-01-14T17:08:04Z

packages/opencode/src/session/index.ts


+  export const getCost = fn(Identifier.schema("session"), async (id) => {
+    const read = await Storage.read<Info>(["session", Instance.project.id, id])
+    return read.cost ?? 0


prefer leaving as undefined so we can properly do checks in frontend right

makes sense, updated

this informs the caller function that cost can be undefined so it can properly handle it, instead of just defaulting to 0.

…cts style

…to 0

rekram1-node · 2026-01-15T16:50:25Z

packages/opencode/src/storage/storage.ts

+    async (dir) => {
+      log.info("migrating session costs")
+      const startTime = Date.now()
+      let migratedCount = 0
+
+      for await (const sessionPath of new Bun.Glob("session/*/*.json").scan({
+        cwd: dir,
+        absolute: true,
+      })) {


do we have to do a migration?

I think it's fine if only new things are updated, some people have a LOT of sessions

would be awesome to have a way to run the migration manually if its not automatic.

@rekram1-node with the fallback to deriving cost from messages present in the memory (from commit affc11a), migration is not strictly required in a sense that it will break the functionality but for older sessions the cost reporting will still be bugged.

from my local testing the migration was fine but again I don't know the extent of how many sessions people have, it could be a concern.

as @maharshi365 mentioned I can also add lazy migration, that only runs when a session is loaded, checks if the session has cost field, and run the migration if needed. I am currently not aware if users can manually run migrations in OC or not, also if it's fine from maintainers perspective to only updated new sessions I am fine with that as well, let me know @rekram1-node .

I think one time migration is probably way more important than whatever slowness there is in startup. Its not just stale data, but incorrect cost data that is being shown.

…culation

…t makes no difference to use existsSync

okay so fs.stat is used in the codebase instead of existsSync

bluet · 2026-02-05T23:14:28Z

Thanks for this fix! One consideration: addCost() only updates the current session, so subagent costs (via Task tool) won't roll up to parent sessions. For multi-agent workflows, the sidebar will still under-report.

Would you consider adding parent propagation via the existing parentID chain? Happy to discuss or contribute a follow-up PR.

Related: #11027 (subagent costs not aggregated)

I've also filed a comprehensive architecture proposal: #12377

IdrisGit · 2026-02-06T13:48:44Z

@bluet I am happy to discuss further on this, maybe we can have a proper tracking of the main agent cost and subagent cost for a proper breakdown, but first this PR needs to be merged or any improvement suggestions from the core team (cc: @thdxr)

IdrisGit added 3 commits January 10, 2026 23:03

feat(opencode): add cost tracking to the session information

a863bc0

fix(tui): read actual cost from the session informatin instead of der…

ba86463

…iving from the messages array max 100 messages are kept in the store/memory which leads to misreporting of the actual spend value

feat: add migration step to populate old session with cost

9ca6a61

github-actions bot added the needs:issue label Jan 11, 2026

fix: forked sessions should start with $0 spent value

97ee252

github-actions bot removed the needs:issue label Jan 11, 2026

rekram1-node reviewed Jan 14, 2026

View reviewed changes

IdrisGit added 3 commits January 15, 2026 07:15

fix: return undefined instead of 0 if cost is not found

d6dbb1d

this informs the caller function that cost can be undefined so it can properly handle it, instead of just defaulting to 0.

chore: remove log I added for debugging as it doesn't match the proje…

96212fa

…cts style

feat: fallback to deriving cost from messages rather than defaulting …

affc11a

…to 0

IdrisGit requested a review from rekram1-node January 15, 2026 01:57

rekram1-node reviewed Jan 15, 2026

View reviewed changes

IdrisGit requested a review from rekram1-node January 19, 2026 07:47

rekram1-node and others added 5 commits January 25, 2026 11:32

Merge branch 'dev' into fix-session-cost-calculation

4bd7c4a

Merge remote-tracking branch 'upstream/dev' into fix-session-cost-cal…

066aca8

…culation

fix: use existsSync now that exists is also deprecated from Bun and i…

1797fc0

…t makes no difference to use existsSync

fix: use fs.stats instead

76a6f62

okay so fs.stat is used in the codebase instead of existsSync

Merge branch 'dev' into fix-session-cost-calculation

bad10d8

thdxr force-pushed the dev branch from cbab81f to 2d3c7a0 Compare January 30, 2026 04:50

opencode-agent bot force-pushed the dev branch from 00637c0 to 71e0ba2 Compare January 30, 2026 14:32

thdxr force-pushed the dev branch 3 times, most recently from f1ae801 to 08fa7f7 Compare January 30, 2026 14:37

IdrisGit and others added 3 commits January 30, 2026 23:58

Merge branch 'dev' into fix-session-cost-calculation

238521c

Merge branch 'dev' into fix-session-cost-calculation

2975b2d

fix: commit types as I have added new cost key to the session

736f67e

IdrisGit force-pushed the fix-session-cost-calculation branch from b5e01b5 to 736f67e Compare January 31, 2026 14:54

This was referenced Feb 5, 2026

Cost of session doesn't include cost of subagents #11027

Open

Multi Model Cost Calculations are Bugged #7387

Open

[RFC] Cost Tracking Architecture: Subagent Aggregation + Multi-Model Correctness #12377

Closed

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IdrisGit commented Jan 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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What does this PR do?

How did you verify your code works?

OpenCode v1.1.12

OpenCode local

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bluet commented Feb 5, 2026

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IdrisGit commented Feb 6, 2026

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IdrisGit commented Jan 11, 2026 •

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