feat(flags): implement get_feature_flag endpoint in SDK compliance adapter

[andehen]

Problem

The SDK compliance adapter doesn't expose a way to evaluate feature flags, which is needed for cross-SDK compliance testing of flag evaluation.

Changes

• Added a /get_feature_flag POST endpoint to the compliance adapter that wraps client.get_feature_flag()
• Supports person_properties, groups, group_properties, disable_geoip, and force_remote parameters
• Maps force_remote to the inverse of only_evaluate_locally for a cleaner external API

Testing

• Call the /get_feature_flag endpoint with a key and distinct_id after initializing the SDK via the adapter
• Verify flag evaluation with various combinations of person/group properties
• Verify error responses when key or distinct_id are missing or SDK is not initialized

[github-actions]

posthog-python Compliance Report

Date: 2026-04-16 10:50:55 UTC
Duration: 159991ms

✅ All Tests Passed!

30/30 tests passed

---

Capture Tests

✅ 29/29 tests passed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	516ms
Format Validation.Event Has Uuid	✅	1507ms
Format Validation.Event Has Lib Properties	✅	1507ms
Format Validation.Distinct Id Is String	✅	1507ms
Format Validation.Token Is Present	✅	1507ms
Format Validation.Custom Properties Preserved	✅	1507ms
Format Validation.Event Has Timestamp	✅	1507ms
Retry Behavior.Retries On 503	✅	9515ms
Retry Behavior.Does Not Retry On 400	✅	3510ms
Retry Behavior.Does Not Retry On 401	✅	3507ms
Retry Behavior.Respects Retry After Header	✅	9514ms
Retry Behavior.Implements Backoff	✅	23528ms
Retry Behavior.Retries On 500	✅	7507ms
Retry Behavior.Retries On 502	✅	7510ms
Retry Behavior.Retries On 504	✅	7509ms
Retry Behavior.Max Retries Respected	✅	23532ms
Deduplication.Generates Unique Uuids	✅	1498ms
Deduplication.Preserves Uuid On Retry	✅	7510ms
Deduplication.Preserves Uuid And Timestamp On Retry	✅	14522ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	7512ms
Deduplication.No Duplicate Events In Batch	✅	1503ms
Deduplication.Different Events Have Different Uuids	✅	1507ms
Compression.Sends Gzip When Enabled	✅	1507ms
Batch Format.Uses Proper Batch Structure	✅	1507ms
Batch Format.Flush With No Events Sends Nothing	✅	1005ms
Batch Format.Multiple Events Batched Together	✅	1505ms
Error Handling.Does Not Retry On 403	✅	3509ms
Error Handling.Does Not Retry On 413	✅	3508ms
Error Handling.Retries On 408	✅	7514ms

Feature_Flags Tests

✅ 1/1 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	516ms

[greptile-apps]

Prompt To Fix All With AI

This is a comment left during a code review.
Path: sdk_compliance_adapter/adapter.py
Line: 378-393

Comment:
**Inverted default makes endpoint always return `None`**

With `force_remote` defaulting to `False`, the mapping `only_evaluate_locally=not force_remote` sets `only_evaluate_locally=True`. Because the adapter client is initialised without a `personal_api_key`, `_locally_evaluate_flag` never loads flags, always returns `None`, and with `only_evaluate_locally=True` there is no remote fallback — so every unauthenticated call to this endpoint silently returns `{"success": true, "value": null}`.

The SDK's own default for `only_evaluate_locally` is `False` (local first, remote fallback). To preserve that default the `force_remote` default must be `True`:

```suggestion
        force_remote = data.get("force_remote", True)

        if not key:
            return jsonify({"error": "key is required"}), 400
        if not distinct_id:
            return jsonify({"error": "distinct_id is required"}), 400

        value = state.client.get_feature_flag(
            key,
            distinct_id,
            person_properties=person_properties,
            groups=groups,
            group_properties=group_properties,
            disable_geoip=disable_geoip,
            only_evaluate_locally=not force_remote,
        )
```

How can I resolve this? If you propose a fix, please make it concise.

_{Reviews (1): Last reviewed commit: "implement flags endpoint" | Re-trigger Greptile}

[andehen]

@marandaneto Thanks! Wasn't expecting a review yet. Created this as part of testing the SDK harness addition upstream so I could verify that it worked as intended. But I think it's ready to go as it is now, so thanks! 👍

FYI the plan forward is to add such an adapter to all SDK's that support flags (all I guess?), so we can automatically test that the comply with the flags API and behave similarly wrt. to edge cases, etc.

[marandaneto]

@marandaneto Thanks! Wasn't expecting a review yet. Created this as part of testing the SDK harness addition upstream so I could verify that it worked as intended. But I think it's ready to go as it is now, so thanks! 👍

FYI the plan forward is to add such an adapter to all SDK's that support flags (all I guess?), so we can automatically test that the comply with the flags API and behave similarly wrt. to edge cases, etc.

we can merge it and fix if needed
you can mark a pr as draft, prs got auto assigned because i removed the master branch in favor of main, and then i just reviewed :D
thanks!