fix: stop repeated identical tool call loops

[codeg-dev]

Issue for this PR

Closes #45442

Related: #43603

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Stops a session after 10 consecutive calls with the same tool name and canonical arguments. Before returning to idle, it emits a visible session error so repeated read loops do not continue indefinitely. Tests cover the threshold, below-threshold calls, and alternating arguments.

How did you verify your code works?

• bun test packages/opencode/test/session/prompt.test.ts — 61 passed, 1 skipped, 0 failed
• bun turbo typecheck — 30/30 packages passed

Screenshots / recordings

Not applicable; this is not a UI change.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

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[agentgoblin]

Stops a session after 10 consecutive calls with the same tool name and canonical arguments.

However, there is already a solution for such cases:

https://open-code.ai/en/docs/permissions
doom_loop — triggered when the same tool call repeats 3 times with identical input

For fully automatic operation, it is better to set it to "deny".

It looks like the pull request duplicates existing functionality. Or does it solve the problem in a new way?

[codeg-dev]

It overlaps with doom_loop, but it addresses a different failure boundary. The existing check runs inside the processor for three identical tool parts in a single assistant response and delegates the outcome to the configurable permission rule. This PR checks consecutive identical calls across assistant turns for the same user prompt and emits a session error before another provider turn. That provides a final runtime circuit breaker even when doom_loop is configured as allow (or repeated calls are split across turns).

I rebased the branch onto the current dev and kept the focused regression tests. The three loop-guard tests pass, package typecheck passes, and the repository pre-push hook completed all 30 typecheck tasks.