fix: surface resolved model ids for dynamic models in execution logs …

[omeraplak]

…and spans

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• The commit message follows our guidelines: https://voltagent.dev/docs/community/contributing/#commit-convention

Bugs / Features

• Related issue(s) linked
• Tests for the changes have been added
• Docs have been added / updated
• Changesets have been added https://voltagent.dev/docs/community/contributing/#creating-a-changeset

What is the current behavior?

What is the new behavior?

fixes (issue)

Notes for reviewers

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Summary by cubic

Ensure execution logs and tracing spans show the resolved model ID for dynamic models instead of the generic "dynamic", improving observability and error context.

• Bug Fixes
  • Pass the resolved model to getModelName to surface modelId in logs and spans.
  • getModelName now accepts a model or string and returns model.modelId (falls back to "unknown").
  • Error logs use the computed modelName to avoid the "dynamic" placeholder.

^{Written for commit 2035c5e. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes
  • Improved execution logs and spans to display resolved model IDs for dynamic models, enhancing observability and debugging visibility.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 2035c5e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@voltagent/core	Patch

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[coderabbitai]

📝 Walkthrough

Walkthrough

A changelog entry documents a patch release that improves observability by surfacing resolved model IDs for dynamic models in execution logs and spans. The Agent class's getModelName method now accepts an optional model parameter, and call sites are updated to pass the resolved model for more accurate logging.

Changes

Cohort / File(s)	Summary
Changelog Updates \.changeset/bright-singers-fold\.md	Added patch release notes documenting fix to surface resolved model IDs for dynamic models in execution logs and spans
Agent Observability packages/core/src/agent/agent\.ts	Updated getModelName(model?) method signature to accept optional LanguageModel | string parameter; updated multiple call sites in generateText and streamText methods to pass resolved model for improved observability and more accurate model ID logging

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A model's true name, now shining bright,
Dynamic or static, we log it right,
Through spans and logs, the IDs flow,
Better tracing paths for all to know! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description is largely incomplete with required sections left blank (current/new behavior, linked issues, test/doc/changeset confirmation), though an auto-generated summary provides context about the fix.	Complete the PR checklist by checking boxes for changesets (already added) and confirming tests/docs. Fill in 'What is the current behavior?' and 'What is the new behavior?' sections with concrete details.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately reflects the main change: surfacing resolved model IDs for dynamic models in execution logs and spans, matching the changeset entry and code modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

• 📝 Generate docstrings

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📜 Recent review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between ab39d68 and 2035c5e.

📒 Files selected for processing (2)

• .changeset/bright-singers-fold.md
• packages/core/src/agent/agent.ts

🧰 Additional context used

📓 Path-based instructions (1)

**/*.ts

📄 CodeRabbit inference engine (AGENTS.md)

**/*.ts: Maintain type safety in TypeScript-first codebase
Never use JSON.stringify; use the safeStringify function instead, imported from @voltagent/internal

Files:

• packages/core/src/agent/agent.ts

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• GitHub Check: cubic · AI code reviewer
• GitHub Check: Test cli
• GitHub Check: Test libsql
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🔇 Additional comments (8)

packages/core/src/agent/agent.ts (7)

558-564: LGTM! Resolved model correctly passed to getModelName.

The resolved model from prepareExecution is now passed to getModelName(model), ensuring the actual model ID (e.g., gpt-4o) is surfaced in logs and spans rather than "dynamic" for dynamic model configurations.

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957-963: LGTM! Consistent with generateText pattern.

The streamText method now correctly passes the resolved model to getModelName(model) for accurate model identification in logs and spans.

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1102-1106: LGTM! Error logging uses resolved model name.

The onError callback correctly uses the modelName variable captured from the closure (defined at line 963), ensuring error logs include the actual resolved model ID.

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1680-1686: LGTM! Consistent pattern in generateObject.

The deprecated generateObject method now also correctly passes the resolved model to getModelName(model).

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1915-1921: LGTM! Consistent pattern in streamObject.

The deprecated streamObject method follows the same pattern for resolving model names.

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2009-2015: LGTM! Consistent error logging pattern.

The onError callback correctly uses the modelName variable captured from the closure.

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4172-4189: LGTM! Backward-compatible enhancement to getModelName.

The updated method signature with the optional model parameter is:

• Backward compatible: Existing callers without arguments continue to work
• Type-safe: Handles both string and LanguageModel types appropriately
• Consistent fallback: Returns "unknown" when modelId is absent, matching existing behavior

The implementation correctly prioritizes the passed model over the instance's this.model, enabling accurate logging for dynamic model configurations.

.changeset/bright-singers-fold.md (1)

1-5: LGTM! Changeset correctly describes the patch.

The changeset format is valid and the patch release type is appropriate for this observability improvement.

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[cubic-dev-ai]

No issues found across 2 files

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