[30bef100w]

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fix

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• The title follows Conventional Commits.
• The title describes the user-visible fix.
• Separate user documentation PR (compatibility notes are included in this repository).

Description

ToolsNode currently aliases tool execution addresses and checkpoint result maps when a model emits empty or duplicate tool-call IDs. Assign deterministic batch-local keys to those calls, reserve the generated namespace against all model IDs, and use the same tool-name/key address for execution and legacy interrupt wrapping. Unique non-empty IDs retain their existing keys. Model-facing ToolCallID values and GetToolCallID remain unchanged.

Use the keys consistently in completed-result maps, rerun metadata and stream checkpoint bookkeeping. ToolCallKeys maps public interrupt metadata back to ToolCalls without requiring consumers to parse the key format.

Refs #1290. This keeps the batch-info accessor work in #1289 separate. It fixes legacy address inconsistency, but does not claim to fix the separate legacy UUID-based resume problem tracked by #1269.

Persisted checkpoint compatibility

New checkpoints carry a key-format version. Old ambiguous-ID checkpoints fail before dispatch because their completed-result maps may already have lost information; silently replaying those tools can repeat side effects. Old unique-ID modern checkpoints retain their address/key format. Legacy wrapper addresses change and old legacy interrupts are not transparently migrated. See docs/tool-call-checkpoint-identities.md for details and rollback limitations. Maintainer review of this compatibility policy is requested.

Validation

• New public-behavior regression tests fail on the original tool_node.go at 4a4b718: 12 duplicate/empty/collision selective-resume cases and 2 legacy address-consistency cases fail; the 4 unique-ID control cases pass.
• With this patch, selective resume passes for empty, repeated, generated-key-like and unique IDs, with both Invoke/Stream and parallel/sequential execution. Tests verify exact outputs, preserved original IDs, stable addresses and that completed tools are not replayed.
• Additional tests cover old ambiguous-checkpoint rejection and standard/enhanced stream checkpoint result maps.
• go test ./compose -count=1: PASS.
• go vet ./compose: PASS.
• golangci-lint run --new-from-rev=4a4b7186693d9805539c7f0c36db7d03a3485c6a ./compose/...: 0 issues.
• git diff --check: PASS.
• Full-repository tests, production workloads and legacy UUID-based selective resume are not claimed as validated.

Implemented and tested with OpenAI Codex at the author's request. Independent human author review has not been completed; maintainer review is requested.

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