test(gemini): assert tool turns reach $ai_input as normalized blocks

[marco-g-pm]

💡 Motivation and Context

Follow-up to #823, which fixed the Gemini tool block shapes for #725. That PR tested the converter. This one tests the payload PostHog actually receives.

The gap mattered. A converter test proves format_gemini_input returns the right dict. It does not prove that dict reaches $ai_input, survives the capture path, and stays JSON-serializable.

Changes

One test. It drives the whole path with a mocked google-genai client and real types.Content objects, then reads the $ai_input property handed to capture():

• the text turn stays a text block
• the model turn becomes {"type": "function", "function": {name, arguments}}
• the tool-response turn becomes {"type": "function", "tool_name": ..., "content": ...}
• the whole payload survives a JSON round trip

💚 How did you test it?

I ran the test against the pre-fix converter to confirm it catches the original bug:

At index 0 diff:
  {'type': 'function_call', 'function_call': {'args': {'city': 'SF'}, 'name': 'get_weather'}}
!={'type': 'function',      'function':      {'name': 'get_weather', 'arguments': {'city': 'SF'}}}

That is the exact defect from #725. A test that cannot fail is not worth adding.

On current main, posthog/test/ai/gemini/ gives 74 pass and 5 skip.

I also fed the captured payload through both downstream consumers:

• The trace view guards sort it correctly. The call reads as a tool step. The response reads as a tool result, so isInternalToolResultUserMessage hides it instead of letting it leak as a user bubble.
• The eval formatter prints the tool output as [FUNCTION] {'temp_c': 18}, which is what the judge needs.

No live Gemini key and no real project.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran sampo add to generate a changeset file

Tests only, so there is nothing to release.

A gap this test surfaced

The eval formatter still prints a Gemini tool call as a raw dict dump. _format_special_block returns None for type: "function" and leaves it to the message-level tool_calls field, which this payload does not use. Anthropic tool_use and OpenAI tool_calls both print a clean call.

This predates #823. The SDK already used that block for $ai_output_choices, so Gemini tool calls have always printed this way for the judge. The fix belongs in message_formatter.py, not here.

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Written with Claude Code (Opus 5), directed by @marco-g-pm.

I wrote this after #823 merged, so it lands as its own PR. The end-to-end run is also what surfaced the eval formatter gap above, which no converter test could have shown.

[github-actions]

posthog-python Compliance Report

Date: 2026-08-05 19:02:44 UTC
Duration: 256042ms

✅ All Tests Passed!

111/111 tests passed

---

Capture_V1 Tests

✅ 94/94 tests passed

View Details

Test	Status	Duration
Endpoint And Method.Targets V1 Endpoint	✅	513ms
Endpoint And Method.Does Not Use Legacy Endpoints	✅	509ms
Required Headers.Has Authorization Bearer Header	✅	508ms
Required Headers.Has Content Type Json	✅	509ms
Required Headers.Has Posthog Sdk Info Format	✅	508ms
Required Headers.Has Posthog Attempt Header	✅	508ms
Required Headers.Has Posthog Request Id	✅	509ms
Required Headers.Has Posthog Request Timestamp	✅	507ms
Required Headers.Has User Agent	✅	509ms
Body Format.Body Has Created At And Batch	✅	508ms
Body Format.No Api Key In Body	✅	509ms
Body Format.No Sent At In Body	✅	508ms
Event Format.Event Has Required Root Fields	✅	508ms
Event Format.Event Uuid Is Valid	✅	508ms
Event Format.Event Timestamp Is Rfc3339	✅	508ms
Event Format.Distinct Id Is String	✅	508ms
Event Format.Distinct Id At Root Not Properties	✅	508ms
Event Format.Custom Properties Preserved	✅	511ms
Event Format.Set Properties Preserved	✅	508ms
Event Format.Set Once Properties Preserved	✅	509ms
Event Format.Groups Properties Preserved	✅	509ms
Event Format.Sdk Generates Uuid If Not Provided	✅	508ms
Event Format.Event Has Required Root Fields Batch	✅	511ms
Event Format.Event Uuid Is Valid Batch	✅	510ms
Event Format.Event Timestamp Is Rfc3339 Batch	✅	511ms
Event Format.Distinct Id Is String Batch	✅	511ms
Event Format.Distinct Id At Root Not Properties Batch	✅	511ms
Event Format.Custom Properties Preserved Batch	✅	510ms
Event Format.Set Properties Preserved Batch	✅	511ms
Event Format.Set Once Properties Preserved Batch	✅	510ms
Event Format.Groups Properties Preserved Batch	✅	511ms
Event Format.Sdk Generates Uuid If Not Provided Batch	✅	511ms
Batch Behavior.Multiple Events In Single Batch	✅	513ms
Batch Behavior.Batch Envelope Smoke	✅	512ms
Batch Behavior.Flush With No Events Sends Nothing	✅	505ms
Batch Behavior.Flush At Triggers Batch	✅	1009ms
Batch Behavior.Created At Reflects Batch Creation Time	✅	509ms
Deduplication.Generates Unique Uuids	✅	513ms
Deduplication.Different Events Same Content Different Uuids	✅	510ms
Deduplication.Preserves Uuid On Retry	✅	6517ms
Deduplication.Preserves Timestamp On Retry	✅	6518ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	6519ms
Deduplication.No Duplicate Events In Batch	✅	515ms
Header Behavior On Retry.Attempt Header Starts At One	✅	508ms
Header Behavior On Retry.Attempt Header Increments On Retry	✅	13517ms
Header Behavior On Retry.Request Id Preserved On Retry	✅	6515ms
Header Behavior On Retry.Different Requests Have Different Request Ids	✅	3016ms
Header Behavior On Retry.Request Timestamp Changes On Retry	✅	6517ms
Response Format Validation.Success Response Has Uuid Keyed Results	✅	508ms
Response Format Validation.Success Response Has Ok For Each Event	✅	512ms
Response Format Validation.Success No Retry After When All Ok	✅	510ms
Response Format Validation.Success Retry After Present When Retry Events	✅	1513ms
Response Format Validation.Success No Retry After When Drop Only	✅	510ms
Response Format Validation.Response Echoes Request Id	✅	509ms
Retry Behavior.Retries On 408	✅	6516ms
Retry Behavior.Retries On 500	✅	6517ms
Retry Behavior.Retries On 503	✅	8520ms
Retry Behavior.Retries On 504	✅	6517ms
Retry Behavior.Retryable Errors Have Retry After	✅	3515ms
Retry Behavior.Respects Retry After On Retryable Error	✅	11520ms
Retry Behavior.Does Not Retry On 400	✅	2511ms
Retry Behavior.Does Not Retry On 401	✅	2510ms
Retry Behavior.Does Not Retry On 402	✅	2511ms
Retry Behavior.Does Not Retry On 413	✅	2511ms
Retry Behavior.Does Not Retry On 415	✅	2510ms
Retry Behavior.Non Retryable Errors Have No Retry After	✅	2511ms
Retry Behavior.Implements Backoff	✅	22533ms
Retry Behavior.Max Retries Respected	✅	22533ms
Partial Batch Handling.Handles 200 Full Success	✅	2511ms
Partial Batch Handling.Handles 200 With All Ok	✅	3513ms
Partial Batch Handling.Does Not Retry Dropped Events	✅	3511ms
Partial Batch Handling.Does Not Retry Limited Events	✅	3510ms
Partial Batch Handling.Prunes Ok Events On Partial Retry	✅	6519ms
Partial Batch Handling.Prunes Dropped Events On Partial Retry	✅	6518ms
Partial Batch Handling.Retries Only Retry Events From Partial	✅	6519ms
Partial Batch Handling.Partial Retry Preserves Uuids	✅	6515ms
Partial Batch Handling.Partial Retry Attempt Header Increments	✅	6518ms
Partial Batch Handling.Partial Retry Request Id Preserved	✅	6515ms
Partial Batch Handling.Respects Retry After On Partial	✅	8518ms
Partial Batch Handling.Unknown Result Treated As Terminal	✅	3511ms
Partial Batch Handling.Mixed Ok Drop Limited No Retry	✅	3516ms
Compression.Sends Gzip Content Encoding	✅	509ms
Compression.No Content Encoding When Disabled	✅	508ms
Compression.Compressed Body Is Decompressible	✅	509ms
Error Handling.Does Not Retry On Unknown 4Xx	✅	2510ms
Event Options.Cookieless Mode Override	✅	508ms
Event Options.Disable Skew Correction Override	✅	508ms
Event Options.Process Person Profile Override	✅	509ms
Event Options.Product Tour Id Override	✅	508ms
Event Options.Unset Options Omitted	✅	508ms
Event Options.Options Override In Batch	✅	510ms
Geoip And Historical Migration.Geoip Disable Injected Into Properties	✅	508ms
Geoip And Historical Migration.Historical Migration Set In Body	✅	508ms
Geoip And Historical Migration.Historical Migration Absent By Default	✅	508ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	8ms
Request Payload.Flags Request Uses V2 Query Param	✅	7ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	7ms
Request Payload.Flags Request Omits Authorization Header	✅	7ms
Request Payload.Token In Flags Body Matches Init	✅	7ms
Request Payload.Groups Round Trip	✅	7ms
Request Payload.Groups Default To Empty Object	✅	6ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	8ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	6ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	7ms
Request Lifecycle.No Flags Request On Init Alone	✅	3ms
Request Lifecycle.No Flags Request On Normal Capture	✅	507ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	✅	11ms
Request Lifecycle.Mock Response Value Is Returned To Caller	✅	7ms
Retry Behavior.Retries Flags On 502	✅	310ms
Retry Behavior.Retries Flags On 504	✅	311ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	509ms