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feat(mcp): resolve fresh low-level tool ownership - #1009

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feat(mcp): resolve fresh low-level tool ownership#1009
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@gesh gesh commented Oct 5, 2026

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💡 Motivation and Context

Fresh low-level MCP server instances might call a strict tool before they serve tools/list. The SDK then cannot remove its injected arguments before tool validation.

Why: Strict tools must receive only their own arguments. This change follows sdk-specs#98.

💚 How did you test it?

  • Ran focused MCP SDK 1.x tests.
  • Ran the complete MCP SDK 2.x test suite.
  • Ran Ruff, mypy, the public API check, and the import warning check.

📝 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.

🤖 Agent context

Autonomy: Human-driven (agent-assisted)

PostHog Desktop Codex implemented the agreed SDK contract. The implementation keeps unknown ownership fail-open and gives served listings priority over the resolver.

Created with PostHog Desktop

@gesh
feat(mcp): resolve fresh low-level tool ownership
a5f9b4f 
Add resolve_original_tool for raw MCP SDK 1.x and 2.x servers. Prefer ownership learned from a served listing and keep unknown ownership fail-open.

Generated-By: PostHog Desktop
Task-Id: db1a8a08-fe03-43b6-9e49-705e8b1f375e
@gesh gesh self-assigned this Oct 5, 2026
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github-actions Bot commented Oct 5, 2026 •
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posthog-python Compliance Report

Date: 2026-10-05T14:33:13.760206+00:00
Duration: 259492ms

✅ 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 ✅ 518ms
Endpoint And Method.Does Not Use Legacy Endpoints ✅ 511ms
Required Headers.Has Authorization Bearer Header ✅ 508ms
Required Headers.Has Content Type Json ✅ 511ms
Required Headers.Has Posthog Sdk Info Format ✅ 508ms
Required Headers.Has Posthog Attempt Header ✅ 510ms
Required Headers.Has Posthog Request Id ✅ 508ms
Required Headers.Has Posthog Request Timestamp ✅ 510ms
Required Headers.Has User Agent ✅ 508ms
Body Format.Body Has Created At And Batch ✅ 509ms
Body Format.No Api Key In Body ✅ 510ms
Body Format.No Sent At In Body ✅ 508ms
Event Format.Event Has Required Root Fields ✅ 509ms
Event Format.Event Uuid Is Valid ✅ 509ms
Event Format.Event Timestamp Is Rfc3339 ✅ 509ms
Event Format.Non Utc Event Timestamp Is Converted To Utc ✅ 514ms
Event Format.Distinct Id Is String ✅ 509ms
Event Format.Distinct Id At Root Not Properties ✅ 509ms
Event Format.Custom Properties Preserved ✅ 508ms
Event Format.Set Properties Preserved ✅ 509ms
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 ✅ 512ms
Event Format.Event Uuid Is Valid Batch ✅ 511ms
Event Format.Event Timestamp Is Rfc3339 Batch ✅ 512ms
Event Format.Distinct Id Is String Batch ✅ 513ms
Event Format.Distinct Id At Root Not Properties Batch ✅ 512ms
Event Format.Custom Properties Preserved Batch ✅ 512ms
Event Format.Set Properties Preserved Batch ✅ 511ms
Event Format.Set Once Properties Preserved Batch ✅ 512ms
Event Format.Groups Properties Preserved Batch ✅ 511ms
Event Format.Sdk Generates Uuid If Not Provided Batch ✅ 511ms
Batch Behavior.Multiple Events In Single Batch ✅ 514ms
Batch Behavior.Batch Envelope Smoke ✅ 513ms
Batch Behavior.Flush With No Events Sends Nothing ✅ 506ms
Batch Behavior.Flush At Triggers Batch ✅ 1010ms
Batch Behavior.Created At Reflects Batch Creation Time ✅ 510ms
Deduplication.Generates Unique Uuids ✅ 514ms
Deduplication.Different Events Same Content Different Uuids ✅ 511ms
Deduplication.Preserves Uuid On Retry ✅ 6518ms
Deduplication.Preserves Timestamp On Retry ✅ 6515ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry ✅ 6521ms
Deduplication.No Duplicate Events In Batch ✅ 517ms
Header Behavior On Retry.Attempt Header Starts At One ✅ 510ms
Header Behavior On Retry.Attempt Header Increments On Retry ✅ 13525ms
Header Behavior On Retry.Request Id Preserved On Retry ✅ 6518ms
Header Behavior On Retry.Different Requests Have Different Request Ids ✅ 3018ms
Header Behavior On Retry.Request Timestamp Changes On Retry ✅ 6518ms
Response Format Validation.Success Response Has Uuid Keyed Results ✅ 509ms
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 ✅ 511ms
Response Format Validation.Response Echoes Request Id ✅ 508ms
Retry Behavior.Retries On 408 ✅ 6519ms
Retry Behavior.Retries On 500 ✅ 6517ms
Retry Behavior.Retries On 503 ✅ 8517ms
Retry Behavior.Retries On 504 ✅ 6513ms
Retry Behavior.Retryable Errors Have Retry After ✅ 3515ms
Retry Behavior.Respects Retry After On Retryable Error ✅ 11519ms
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 ✅ 2512ms
Retry Behavior.Non Retryable Errors Have No Retry After ✅ 2512ms
Retry Behavior.Implements Backoff ✅ 22533ms
Retry Behavior.Max Retries Respected ✅ 22534ms
Partial Batch Handling.Handles 200 Full Success ✅ 2511ms
Partial Batch Handling.Handles 200 With All Ok ✅ 3515ms
Partial Batch Handling.Does Not Retry Dropped Events ✅ 3515ms
Partial Batch Handling.Does Not Retry Limited Events ✅ 3515ms
Partial Batch Handling.Prunes Ok Events On Partial Retry ✅ 6515ms
Partial Batch Handling.Prunes Dropped Events On Partial Retry ✅ 6521ms
Partial Batch Handling.Retries Only Retry Events From Partial ✅ 6521ms
Partial Batch Handling.Partial Retry Preserves Uuids ✅ 6519ms
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 ✅ 8519ms
Partial Batch Handling.Unknown Result Treated As Terminal ✅ 3512ms
Partial Batch Handling.Mixed Ok Drop Limited No Retry ✅ 3518ms
Compression.Sends Gzip Content Encoding ✅ 509ms
Compression.No Content Encoding When Disabled ✅ 508ms
Compression.Compressed Body Is Decompressible ✅ 508ms
Error Handling.Does Not Retry On Unknown 4Xx ✅ 2510ms
Event Options.Cookieless Mode Override ✅ 509ms
Event Options.Disable Skew Correction Override ✅ 509ms
Event Options.Process Person Profile Override ✅ 508ms
Event Options.Product Tour Id Override ✅ 508ms
Event Options.Unset Options Omitted ✅ 509ms
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 ✅ 509ms

Capture_Ai Tests

✅ 5/5 tests passed

View Details
Test Status Duration
Routing.Capture Ai Posts To Ai Endpoint ✅ 508ms
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 ✅ 509ms

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 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 ✅ 7ms
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 ✅ 12ms
Request Lifecycle.Mock Response Value Is Returned To Caller ✅ 7ms
Retry Behavior.Retries Flags On 502 ✅ 311ms
Retry Behavior.Retries Flags On 504 ✅ 311ms
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 ✅ 53ms
Versioned Boolean Matching.Matching Version 1 ✅ 53ms
Versioned Boolean Matching.Matching Version 2 ✅ 52ms
Versioned Boolean Matching.Version Only Reload 1 2 1 2 Missing ✅ 28ms

@gesh gesh mentioned this pull request Oct 5, 2026
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3 of 5 tasks
@gesh
fix(mcp): preserve listed argument ownership
d863840 
Generated-By: PostHog Desktop
Task-Id: db1a8a08-fe03-43b6-9e49-705e8b1f375e

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