[Silthus]

💡 Motivation and Context

When you pass a secret_key, the client turns on local evaluation and polls /flags/definitions every 30 seconds. Transactional email asks for a Project Secret API Key with only the transactional_email:write scope. The flags service answers that key with 401 authentication_failed ("Secret API token is invalid."), the same answer as a wrong key, because its key lookup only finds keys with a flag scope. A personal API key without the scope gets 403 permission_denied.

So a client that only sends email logged an ERROR about feature flags every 30 seconds, for as long as it ran. 403 also logged an ERROR on every poll.

Merge Danger

Low, two-way door. Only the log level and frequency for 401 and 403 from /flags/definitions change. Polling, flag state (401 still clears definitions), debug-mode raising and remote evaluation are unchanged.

What changes

• On 401 or 403, the client logs one WARNING. It says the key is invalid or lacks the Feature flags: Read scope, and that enable_local_evaluation=False turns local evaluation off.
• Later rejected polls log at DEBUG. The next 200 or 304 re-arms the warning, so a key that breaks later warns again.
• The poller keeps its 30 second cadence. A user who adds the scope gets local evaluation back on the next successful poll, and after a restart.
• 402, other statuses, network errors and remote flag evaluation behave as before.

This PR is independent of the email PR #1171. Both touch posthog/client.py, but in different places, and this diff applies cleanly on that PR's head.

💚 How did you test it?

• New tests in posthog/test/test_feature_flags.py: five polls answered with 401 or 403 log one WARNING (it was five ERRORs before the fix), and a 200 between rejections warns again. They failed before the fix and pass now. test_load_feature_flags_unauthorized and test_load_feature_flags_wrong_key now expect the WARNING.
• pytest posthog/test/: 6096 passed, 25 skipped. ruff format --check, ruff check, mypy | mypy-baseline filter and python -W error -c "import posthog" pass.
• Test seam: Client._load_feature_flags with posthog.client.get mocked to raise APIError.
• Live run: a real Posthog client with secret_key and poll_interval=1 polled a local stub of /flags/definitions that sends the flags service's 401 and 403 bodies. Over 9 polls (three 401s, a 200, then 401s) it logged two WARNINGs, one before and one after the load. Five 403s logged one. The same run on main logged 8 ERRORs.
• Gap: no run against PostHog itself with a scope-less key. The stub's 401 and 403 come from reading rust/feature-flags/src/api/auth.rs and errors.rs in PostHog/posthog.

📝 Checklist

• All commits are signed (see Commit signing)
• 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

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Claude Code (Claude Opus 5.5) wrote the change test-first in a T3 Code thread, as a side fix from the transactional email work. GPT-6.1 Sol reviewed the diff before the push and found nothing that holds. The same fix is going to posthog-node, posthog-go, posthog-php and posthog-elixir.

Question	Answer	Who	Where
Which responses count as a key that can't read flags?	401 and 403, because the flags service answers a scope-less project secret key with the same 401 as a wrong key	🤖 Agent	comment
Stop polling or keep polling quietly?	Keep polling at 30 seconds and stay quiet, so a transient 401 or an added scope recovers without a restart	🤖 Agent	comment
Which channel reports it?	One WARNING on the posthog logger, then DEBUG	🤖 Agent	comment

Involvement: one cross-family review (GPT-6.1 Sol), no grilling rounds, live-run proof against a local stub of the flags service.

🤖 Generated with Claude Code

[Silthus]

Note

🤖 Claude Opus 5.5 responding on behalf of Michael

Decisions made while building this fix:

• 🤖 Which responses count as a key that can't read flags? 401 and 403. The flags service answers a project secret key without the flag scope with the same 401 as a wrong key, so the SDK can't tell them apart and the message names both causes.
• 🤖 Stop polling or keep polling quietly? Keep polling at the existing cadence and log nothing more until definitions load. Stopping would turn a transient 401 into a dead poller until restart.
• 🤖 Which channel reports it? The SDK's existing warning or error channel, once. Other statuses keep their current logging.

[posthog]

PostHog Review · Standard · reviewed d584f6d: no findings.

[github-actions]

posthog-python Compliance Report

Date: 2026-11-05T12:14:49.489922+00:00
Duration: 259322ms

✅ All Tests Passed!

121/121 tests passed

---

Capture_V1 Tests

✅ 95/95 tests passed

View Details

Test	Status	Duration
Endpoint And Method.Targets V1 Endpoint	✅	512ms
Endpoint And Method.Does Not Use Legacy Endpoints	✅	508ms
Required Headers.Has Authorization Bearer Header	✅	508ms
Required Headers.Has Content Type Json	✅	507ms
Required Headers.Has Posthog Sdk Info Format	✅	508ms
Required Headers.Has Posthog Attempt Header	✅	508ms
Required Headers.Has Posthog Request Id	✅	507ms
Required Headers.Has Posthog Request Timestamp	✅	508ms
Required Headers.Has User Agent	✅	508ms
Body Format.Body Has Created At And Batch	✅	508ms
Body Format.No Api Key In Body	✅	508ms
Body Format.No Sent At In Body	✅	508ms
Event Format.Event Has Required Root Fields	✅	507ms
Event Format.Event Uuid Is Valid	✅	508ms
Event Format.Event Timestamp Is Rfc3339	✅	508ms
Event Format.Non Utc Event Timestamp Is Converted To Utc	✅	521ms
Event Format.Distinct Id Is String	✅	508ms
Event Format.Distinct Id At Root Not Properties	✅	509ms
Event Format.Custom Properties Preserved	✅	508ms
Event Format.Set Properties Preserved	✅	507ms
Event Format.Set Once Properties Preserved	✅	508ms
Event Format.Groups Properties Preserved	✅	508ms
Event Format.Sdk Generates Uuid If Not Provided	✅	508ms
Event Format.Event Has Required Root Fields Batch	✅	510ms
Event Format.Event Uuid Is Valid Batch	✅	510ms
Event Format.Event Timestamp Is Rfc3339 Batch	✅	510ms
Event Format.Distinct Id Is String Batch	✅	511ms
Event Format.Distinct Id At Root Not Properties Batch	✅	511ms
Event Format.Custom Properties Preserved Batch	✅	511ms
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	✅	510ms
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	✅	1007ms
Batch Behavior.Created At Reflects Batch Creation Time	✅	509ms
Deduplication.Generates Unique Uuids	✅	512ms
Deduplication.Different Events Same Content Different Uuids	✅	510ms
Deduplication.Preserves Uuid On Retry	✅	6516ms
Deduplication.Preserves Timestamp On Retry	✅	6517ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	✅	6517ms
Deduplication.No Duplicate Events In Batch	✅	514ms
Header Behavior On Retry.Attempt Header Starts At One	✅	508ms
Header Behavior On Retry.Attempt Header Increments On Retry	✅	13516ms
Header Behavior On Retry.Request Id Preserved On Retry	✅	6513ms
Header Behavior On Retry.Different Requests Have Different Request Ids	✅	3016ms
Header Behavior On Retry.Request Timestamp Changes On Retry	✅	6514ms
Response Format Validation.Success Response Has Uuid Keyed Results	✅	509ms
Response Format Validation.Success Response Has Ok For Each Event	✅	511ms
Response Format Validation.Success No Retry After When All Ok	✅	510ms
Response Format Validation.Success Retry After Present When Retry Events	✅	1512ms
Response Format Validation.Success No Retry After When Drop Only	✅	509ms
Response Format Validation.Response Echoes Request Id	✅	508ms
Retry Behavior.Retries On 408	✅	6516ms
Retry Behavior.Retries On 500	✅	6517ms
Retry Behavior.Retries On 503	✅	8519ms
Retry Behavior.Retries On 504	✅	6513ms
Retry Behavior.Retryable Errors Have Retry After	✅	3514ms
Retry Behavior.Respects Retry After On Retryable Error	✅	11520ms
Retry Behavior.Does Not Retry On 400	✅	2512ms
Retry Behavior.Does Not Retry On 401	✅	2511ms
Retry Behavior.Does Not Retry On 402	✅	2511ms
Retry Behavior.Does Not Retry On 413	✅	2511ms
Retry Behavior.Does Not Retry On 415	✅	2511ms
Retry Behavior.Non Retryable Errors Have No Retry After	✅	2511ms
Retry Behavior.Implements Backoff	✅	22521ms
Retry Behavior.Max Retries Respected	✅	22531ms
Partial Batch Handling.Handles 200 Full Success	✅	2510ms
Partial Batch Handling.Handles 200 With All Ok	✅	3512ms
Partial Batch Handling.Does Not Retry Dropped Events	✅	3510ms
Partial Batch Handling.Does Not Retry Limited Events	✅	3513ms
Partial Batch Handling.Prunes Ok Events On Partial Retry	✅	6519ms
Partial Batch Handling.Prunes Dropped Events On Partial Retry	✅	6514ms
Partial Batch Handling.Retries Only Retry Events From Partial	✅	6518ms
Partial Batch Handling.Partial Retry Preserves Uuids	✅	6518ms
Partial Batch Handling.Partial Retry Attempt Header Increments	✅	6514ms
Partial Batch Handling.Partial Retry Request Id Preserved	✅	6518ms
Partial Batch Handling.Respects Retry After On Partial	✅	8518ms
Partial Batch Handling.Unknown Result Treated As Terminal	✅	3514ms
Partial Batch Handling.Mixed Ok Drop Limited No Retry	✅	3512ms
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	✅	508ms
Event Options.Product Tour Id Override	✅	508ms
Event Options.Unset Options Omitted	✅	508ms
Event Options.Options Override In Batch	✅	511ms
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

Capture_Ai Tests

✅ 5/5 tests passed

View Details

Test	Status	Duration
Routing.Capture Ai Posts To Ai Endpoint	✅	509ms
Routing.Capture Does Not Reroute Ai Named Events	✅	508ms
Identity.Capture Ai Event Has Uuid	✅	508ms
Identity.Capture Ai Keeps Supplied Uuid	✅	508ms
Timestamp Format.Non Utc Event Timestamp Is Converted To Utc	✅	508ms

Feature_Flags Tests

✅ 17/17 tests passed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	✅	9ms
Request Payload.Flags Request Uses V4 Query Param	✅	6ms
Request Payload.Flags Request Hits Flags Path Not Decide	✅	6ms
Request Payload.Flags Request Omits Authorization Header	✅	6ms
Request Payload.Token In Flags Body Matches Init	✅	7ms
Request Payload.Groups Round Trip	✅	6ms
Request Payload.Groups Default To Empty Object	✅	7ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	✅	6ms
Request Payload.Disable Geoip Omitted Defaults To False	✅	6ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	✅	6ms
Request Lifecycle.No Flags Request On Init Alone	✅	3ms
Request Lifecycle.No Flags Request On Normal Capture	✅	506ms
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	✅	310ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	✅	509ms

Feature_Flags_Local_Evaluation Tests

✅ 4/4 tests passed

View Details

Test	Status	Duration
Versioned Boolean Matching.Matching Version Missing	✅	48ms
Versioned Boolean Matching.Matching Version 1	✅	46ms
Versioned Boolean Matching.Matching Version 2	✅	45ms
Versioned Boolean Matching.Version Only Reload 1 2 1 2 Missing	✅	25ms

[github-actions]

SDK performance: posthog-python

Benchmarks completed. No changes flagged for review.

Flags require at least a 5% change in the median and all six pairs agreeing on direction. This is a noise filter, not proof of a performance change or a CI gate.

View all results

Test	Measurement	Before PR	With PR	Change	Assessment
Capture and deliver events (32-byte payload, burst) Shard: capture	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Capture and deliver events (32-byte payload, steady) Shard: capture	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Queue an event (32-byte payload) Shard: capture	Allocated memory per operation	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​; head:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​
Queue an event (32-byte payload) Shard: capture	Allocations per operation	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​; head:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​
Queue an event (4,096-byte payload) Shard: capture	Allocated memory per operation	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​; head:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​
Queue an event (4,096-byte payload) Shard: capture	Allocations per operation	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​; head:​ Background preparation has no public completion boundary before flush; see capture.​drain for full-pipeline allocations.​
Evaluate 1,000 flags under concurrent load Shard: flags-memory	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Refresh 1,000 flag definitions Shard: flags-memory	Managed heap after settling	—	—	—	unavailable; base:​ unsupported; head:​ unsupported; base:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​; head:​ CPython has no uninstrumented total managed-heap byte counter; tracing would distort this RSS pass.​
Capture and deliver events (32-byte payload, burst) Shard: capture	Allocated memory per operation	113.54 KiB/op	113.54 KiB/op	<0.1% less memory	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Allocations per operation	1,096.6 count/op	1,096.59 count/op	<0.1% fewer	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Time per operation	74.64 µs/op	76.48 µs/op	2.5% more time	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Idle process memory (RSS)	35.98 MiB	35.93 MiB	0.1% less memory	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Observed peak process memory (RSS)	37.74 MiB	37.69 MiB	0.2% less memory	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Process memory after settling (RSS)	37.75 MiB	37.69 MiB	0.2% less memory	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Process CPU time per operation	75.87 µs/op	78.41 µs/op	3.3% more time	Not flagged
Capture and deliver events (32-byte payload, burst) Shard: capture	Lifetime peak process memory (RSS)	40.46 MiB	40.46 MiB	No observed change	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Allocated memory per operation	166.1 KiB/op	166.1 KiB/op	<0.1% less memory	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Allocations per operation	1,089.58 count/op	1,089.49 count/op	<0.1% fewer	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Time per operation	105.04 µs/op	98.93 µs/op	5.8% less time	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Idle process memory (RSS)	40.78 MiB	40.75 MiB	<0.1% less memory	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Observed peak process memory (RSS)	45.88 MiB	45.86 MiB	<0.1% less memory	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Process memory after settling (RSS)	45.89 MiB	45.86 MiB	<0.1% less memory	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Process CPU time per operation	98.85 µs/op	91.64 µs/op	7.3% less time	Not flagged
Capture and deliver events (4,096-byte payload, burst) Shard: capture	Lifetime peak process memory (RSS)	50.7 MiB	50.73 MiB	<0.1% more memory	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Allocated memory per operation	117.68 KiB/op	117.68 KiB/op	<0.1% less memory	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Allocations per operation	1,136.56 count/op	1,136.55 count/op	<0.1% fewer	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Time per operation	85.15 µs/op	86.02 µs/op	1% more time	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Idle process memory (RSS)	35.83 MiB	35.85 MiB	<0.1% more memory	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Observed peak process memory (RSS)	35.96 MiB	35.96 MiB	<0.1% more memory	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Process memory after settling (RSS)	35.96 MiB	35.96 MiB	<0.1% more memory	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Process CPU time per operation	82.3 µs/op	82.16 µs/op	0.2% less time	Not flagged
Capture and deliver events (32-byte payload, steady) Shard: capture	Lifetime peak process memory (RSS)	40.46 MiB	40.46 MiB	No observed change	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Allocated memory per operation	170.57 KiB/op	170.57 KiB/op	<0.1% less memory	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Allocations per operation	1,129.51 count/op	1,129.47 count/op	<0.1% fewer	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Time per operation	113.33 µs/op	115.02 µs/op	1.5% more time	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Idle process memory (RSS)	40.62 MiB	40.53 MiB	0.2% less memory	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Observed peak process memory (RSS)	40.65 MiB	40.55 MiB	0.2% less memory	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Process memory after settling (RSS)	40.65 MiB	40.55 MiB	0.2% less memory	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Process CPU time per operation	104.67 µs/op	109 µs/op	4.1% more time	Not flagged
Capture and deliver events (4,096-byte payload, steady) Shard: capture	Lifetime peak process memory (RSS)	40.91 MiB	40.89 MiB	<0.1% less memory	Not flagged
Queue an event (32-byte payload) Shard: capture	Caller-thread CPU time per operation	49.54 µs/op	48.52 µs/op	2.1% less time	Not flagged
Queue an event (32-byte payload) Shard: capture	Time per operation	54.24 µs/op	48.61 µs/op	10.4% less time	Not flagged
Queue an event (4,096-byte payload) Shard: capture	Caller-thread CPU time per operation	50.54 µs/op	50.6 µs/op	0.1% more time	Not flagged
Queue an event (4,096-byte payload) Shard: capture	Time per operation	50.53 µs/op	51.22 µs/op	1.4% more time	Not flagged
Evaluate all 10 flags Shard: flags-scaling	Allocated memory per operation	200.98 KiB/op	200.98 KiB/op	No observed change	Not flagged
Evaluate all 10 flags Shard: flags-scaling	Allocations per operation	2,339.33 count/op	2,339.33 count/op	No observed change	Not flagged
Evaluate all 10 flags Shard: flags-scaling	Time per operation	115.12 µs/op	114.56 µs/op	0.5% less time	Not flagged
Evaluate all 10 flags Shard: flags-scaling	Process CPU time per operation	115.12 µs/op	114.55 µs/op	0.5% less time	Not flagged
Evaluate all 100 flags Shard: flags-scaling	Allocated memory per operation	1.93 MiB/op	1.93 MiB/op	No observed change	Not flagged
Evaluate all 100 flags Shard: flags-scaling	Allocations per operation	23,013.56 count/op	23,013.56 count/op	No observed change	Not flagged
Evaluate all 100 flags Shard: flags-scaling	Time per operation	1.12 ms/op	1.12 ms/op	0.5% more time	Not flagged
Evaluate all 100 flags Shard: flags-scaling	Process CPU time per operation	1.12 ms/op	1.12 ms/op	0.5% more time	Not flagged
Evaluate all 1,000 flags Shard: flags-scaling	Allocated memory per operation	19.24 MiB/op	19.24 MiB/op	No observed change	Not flagged
Evaluate all 1,000 flags Shard: flags-scaling	Allocations per operation	229,654.94 count/op	229,654.94 count/op	No observed change	Not flagged
Evaluate all 1,000 flags Shard: flags-scaling	Time per operation	11.2 ms/op	11.31 ms/op	1% more time	Not flagged
Evaluate all 1,000 flags Shard: flags-scaling	Process CPU time per operation	11.2 ms/op	11.31 ms/op	1% more time	Not flagged
Evaluate 1,000 flags under concurrent load Shard: flags-memory	Idle process memory (RSS)	42.38 MiB	42.26 MiB	0.3% less memory	Not flagged
Evaluate 1,000 flags under concurrent load Shard: flags-memory	Observed peak process memory (RSS)	42.77 MiB	42.62 MiB	0.4% less memory	Not flagged
Evaluate 1,000 flags under concurrent load Shard: flags-memory	Process memory after settling (RSS)	42.77 MiB	42.62 MiB	0.4% less memory	Not flagged
Evaluate 1,000 flags under concurrent load Shard: flags-memory	Lifetime peak process memory (RSS)	42.58 MiB	42.39 MiB	0.5% less memory	Not flagged
Refresh 1,000 flag definitions Shard: flags-memory	Idle process memory (RSS)	42.08 MiB	42.04 MiB	0.1% less memory	Not flagged
Refresh 1,000 flag definitions Shard: flags-memory	Observed peak process memory (RSS)	42.12 MiB	42.11 MiB	<0.1% less memory	Not flagged
Refresh 1,000 flag definitions Shard: flags-memory	Process memory after settling (RSS)	41.45 MiB	42.09 MiB	1.5% more memory	Not flagged
Refresh 1,000 flag definitions Shard: flags-memory	Lifetime peak process memory (RSS)	42.51 MiB	42.48 MiB	<0.1% less memory	Not flagged
Evaluate one boolean flag Shard: flags-single	Allocated memory per operation	15.05 KiB/op	15.05 KiB/op	No observed change	Not flagged
Evaluate one boolean flag Shard: flags-single	Allocations per operation	173.76 count/op	173.76 count/op	No observed change	Not flagged
Evaluate one boolean flag Shard: flags-single	Time per operation	13.89 µs/op	13.96 µs/op	0.5% more time	Not flagged
Evaluate one boolean flag Shard: flags-single	Process CPU time per operation	13.89 µs/op	13.96 µs/op	0.5% more time	Not flagged
Evaluate a cohort-filtered flag Shard: flags-single	Allocated memory per operation	23.12 KiB/op	23.12 KiB/op	No observed change	Not flagged
Evaluate a cohort-filtered flag Shard: flags-single	Allocations per operation	270.27 count/op	270.27 count/op	No observed change	Not flagged
Evaluate a cohort-filtered flag Shard: flags-single	Time per operation	21.56 µs/op	21.85 µs/op	1.4% more time	Not flagged
Evaluate a cohort-filtered flag Shard: flags-single	Process CPU time per operation	21.55 µs/op	21.85 µs/op	1.4% more time	Not flagged
Evaluate a flag (early match) Shard: flags-single	Allocated memory per operation	35.71 KiB/op	35.71 KiB/op	No observed change	Not flagged
Evaluate a flag (early match) Shard: flags-single	Allocations per operation	387.27 count/op	387.27 count/op	No observed change	Not flagged
Evaluate a flag (early match) Shard: flags-single	Time per operation	27.19 µs/op	27.43 µs/op	0.9% more time	Not flagged
Evaluate a flag (early match) Shard: flags-single	Process CPU time per operation	27.19 µs/op	27.42 µs/op	0.9% more time	Not flagged
Evaluate a flag (late match) Shard: flags-single	Allocated memory per operation	53.59 KiB/op	53.59 KiB/op	No observed change	Not flagged
Evaluate a flag (late match) Shard: flags-single	Allocations per operation	576.27 count/op	576.27 count/op	No observed change	Not flagged
Evaluate a flag (late match) Shard: flags-single	Time per operation	38.23 µs/op	38.38 µs/op	0.4% more time	Not flagged
Evaluate a flag (late match) Shard: flags-single	Process CPU time per operation	38.23 µs/op	38.38 µs/op	0.4% more time	Not flagged
Evaluate a flag (no match) Shard: flags-single	Allocated memory per operation	52.14 KiB/op	52.14 KiB/op	No observed change	Not flagged
Evaluate a flag (no match) Shard: flags-single	Allocations per operation	556.77 count/op	556.77 count/op	No observed change	Not flagged
Evaluate a flag (no match) Shard: flags-single	Time per operation	34.51 µs/op	34.91 µs/op	1.2% more time	Not flagged
Evaluate a flag (no match) Shard: flags-single	Process CPU time per operation	34.51 µs/op	34.91 µs/op	1.2% more time	Not flagged
Evaluate a property-filtered flag Shard: flags-single	Allocated memory per operation	17.84 KiB/op	17.84 KiB/op	No observed change	Not flagged
Evaluate a property-filtered flag Shard: flags-single	Allocations per operation	198.27 count/op	198.27 count/op	No observed change	Not flagged
Evaluate a property-filtered flag Shard: flags-single	Time per operation	16.39 µs/op	16.48 µs/op	0.5% more time	Not flagged
Evaluate a property-filtered flag Shard: flags-single	Process CPU time per operation	16.38 µs/op	16.48 µs/op	0.6% more time	Not flagged
Evaluate a regex-filtered flag Shard: flags-single	Allocated memory per operation	19.23 KiB/op	19.23 KiB/op	No observed change	Not flagged
Evaluate a regex-filtered flag Shard: flags-single	Allocations per operation	210.77 count/op	210.77 count/op	No observed change	Not flagged
Evaluate a regex-filtered flag Shard: flags-single	Time per operation	17.35 µs/op	17.23 µs/op	0.7% less time	Not flagged
Evaluate a regex-filtered flag Shard: flags-single	Process CPU time per operation	17.35 µs/op	17.23 µs/op	0.7% less time	Not flagged
Evaluate a rollout flag Shard: flags-single	Allocated memory per operation	14.04 KiB/op	14.04 KiB/op	No observed change	Not flagged
Evaluate a rollout flag Shard: flags-single	Allocations per operation	160.76 count/op	160.76 count/op	No observed change	Not flagged
Evaluate a rollout flag Shard: flags-single	Time per operation	13.15 µs/op	12.97 µs/op	1.4% less time	Not flagged
Evaluate a rollout flag Shard: flags-single	Process CPU time per operation	13.15 µs/op	12.97 µs/op	1.4% less time	Not flagged
Evaluate a multivariate flag Shard: flags-single	Allocated memory per operation	15.21 KiB/op	15.21 KiB/op	No observed change	Not flagged
Evaluate a multivariate flag Shard: flags-single	Allocations per operation	177.77 count/op	177.77 count/op	No observed change	Not flagged
Evaluate a multivariate flag Shard: flags-single	Time per operation	14.42 µs/op	14.5 µs/op	0.6% more time	Not flagged
Evaluate a multivariate flag Shard: flags-single	Process CPU time per operation	14.42 µs/op	14.5 µs/op	0.6% more time	Not flagged

Values are medians of paired measurements. Not flagged does not mean unchanged. Unavailable means a measurement could not be provided, not zero. Estimated allocation measurements retain their instrumentation uncertainty. RSS measures the whole process, not just SDK allocations; observed peaks are sampled checkpoints. Paired ranges in the diagnostics describe variability, not confidence intervals.

Each shard uses its own runner; compare Before PR against With PR within a row, not across shards.

Compared db52a785f2d40f6813f25309fd2a7ea3e28aa59a → d584f6d1bc5474f8c9ee40b1eb221976c4beedbf.

Full report and diagnostics

102 metric rows; 102 rows shown in all results. Omitted or shortened data remain in comparison.json, including per-runner environments, resource limits, measurement methods, samples and checkpoints.