ref(langchain): Stop setting gen_ai.tool.definitions on Invoke Agent spans

[alexander-alderman-webb]

Description

Remove the available tools from Invoke Agent spans because it is ambiguous for an agent that makes multiple model calls in the course of its execution. Each model call can have different available tools.

Issues

Reminders

• Please add tests to validate your changes, and lint your code using uv run ruff.
• Add GH Issue ID & Linear ID (if applicable)
• PR title should use conventional commit style (feat:, fix:, ref:, meta:)
• For external contributors: CONTRIBUTING.md, Sentry SDK development docs, Discord community

[github-actions]

Codecov Results 📊

✅ 66063 passed | ⏭️ 2999 skipped | Total: 69062 | Pass Rate: 95.66% | Execution Time: 186m 24s

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2071 uncovered lines.

---

Generated by Codecov Action

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

Want reviews to match your repository better? Bugbot Learning can learn team-specific rules from PR activity. A team admin can enable Learning in the Cursor dashboard.

^{Reviewed by Cursor Bugbot for commit f47fc82. Configure here.}