Source: https://internal-agents.com/agents/posthog-stamphog # PostHog — StampHog A GitHub-label-triggered PR approval agent that applies fail-closed deterministic safety gates, asks an LLM to check for showstoppers, autonomously approves eligible changes, and refuses or escalates the rest. - Approach type: Background agent - Deployment stage: Scaled - Autonomy: Autonomous - Evidence strength: Detailed primary - Status: Open sourced - First reported year: 2026 - Work: Code review - Interfaces: Github, Ci - Invocation: Background, Event driven - Entry reviewed: 2026-09-09 ## Where people stay involved - **eligible pull request → approval decision** — Exception only · Level 5 ## Overview ### Summary A GitHub-label-triggered PR approval agent that applies fail-closed deterministic safety gates, asks an LLM to check for showstoppers, autonomously approves eligible changes, and refuses or escalates the rest. Fact · Reported · High confidence · `posthog-stamphog--summary` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) · Add a PR auto-stamper - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, How it works ## How it works ### Supporting component Draft state, conflicts, requested changes, sensitive paths, size ceilings, and risk tiers can block AI approval; the LLM may tighten but never loosen a gate Fact · Reported · High confidence · `posthog-stamphog--primitives-0` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, How it works ### Supporting component Eligible changes can be approved while risky, ambiguous, or insufficiently assured changes are refused or escalated to a suitable human reviewer Fact · Reported · High confidence · `posthog-stamphog--primitives-1` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) · Add a PR auto-stamper - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, LLM Review ### Supporting component Each run records PR metadata, classification, gate results, reviewer output, and the final verdict Fact · Reported · High confidence · `posthog-stamphog--primitives-2` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Evidence bundle ## Supervision evidence ### Operating model assessment Level 5 for eligible pull request → approval decision; human attention boundary: exception-only. Inference · Catalog judgment · High confidence · `posthog-stamphog--operating-models-0` Confidence reason: Eligible pull requests are approved automatically; risky or ambiguous cases are refused or routed to a human. Qualifications: - Observation date: 2026-07-09 Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) ## Implementation details ### Harness A GitHub Action invokes a Python pipeline that fetches and classifies a PR, applies hard gates, waits for in-flight reviewer bots, runs an LLM review, and posts a verdict Fact · Reported · High confidence · `posthog-stamphog--architecture-harness` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, How it works and Architecture ### Model Claude through the Claude Agent SDK, with Read, Grep, and Glob tools Fact · Reported · High confidence · `posthog-stamphog--architecture-model` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, LLM Review ### Interfaces github, ci Fact · Reported · High confidence · `posthog-stamphog--architecture-interfaces` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Usage ### Tool access Reads the diff and repository files plus trusted review-state, discussion, ownership, and reviewer signals Fact · Reported · High confidence · `posthog-stamphog--architecture-tool-access` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, LLM Review ### Knowledge Repository-specific deny categories, size and risk tiers calibrated from prior human approvals, review guidance, and ownership data Fact · Reported · High confidence · `posthog-stamphog--architecture-knowledge` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Tiers and Empirical basis ### Credentials A dedicated Anthropic organization secret and a StampHog GitHub App token whose approvals satisfy branch protection Fact · Reported · High confidence · `posthog-stamphog--architecture-credentials` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Usage and final verdict ### Context management Each run emits a versioned JSON evidence bundle retained as a CI artifact for 30 days; a sticky GitHub comment carries non-approval verdict history and labels preserve retry state Fact · Reported · High confidence · `posthog-stamphog--architecture-context-mgmt` Confidence reason: A linked first-party source states the claim. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Usage and Evidence bundle ## Reported metrics ### Headline claim Handled 1,600 PRs in the previous month, as reported on July 9, 2026; roughly one in three merged main-repository PRs received its final approval during the reported quarter Metric · Reported · Medium confidence · `posthog-stamphog--headline-metric` Confidence reason: PostHog reports two different windows in its July 9, 2026 article; exact monthly and quarterly boundaries are not supplied. Qualifications: - Reported by: PostHog - Scope: Monthly PRs handled autonomously and quarterly final approvals in the main repository - Denominator: Merged main-repository PRs for the quarterly share; absolute handled PRs for the monthly count - Method: Company-reported production usage - Observation date: 2026-07 Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) · Preserved content.md, lines 105, 118 ### Key observation 1,600 PRs handled autonomously in the previous month, as reported on July 9, 2026 Metric · Reported · Medium confidence · `posthog-stamphog--key-metrics-0` Confidence reason: July 9 is the report date; the source says last month without exact measurement boundaries. Qualifications: - The source does not report the denominator of this figure. - Reported by: PostHog - Scope: PRs handled autonomously in the previous month, as reported on July 9, 2026; exact boundaries unspecified - Method: Company-reported production usage - Observation date: 2026-07-09 Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) · Preserved content.md, lines 118 ### Key observation Roughly one in three PRs merged into PostHog's main repository received StampHog's final approval during the reported quarter Metric · Reported · Medium confidence · `posthog-stamphog--key-metrics-1` Confidence reason: A linked first-party source states the claim. Qualifications: - Reported by: PostHog - Scope: Main-repository merged PRs receiving StampHog final approval during the reported quarter - Denominator: Merged PRs in the main repository - Method: Company-reported production usage - Observation date: 2026-07 Evidence: - Supports · [1] [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-1/content.md) · Preserved content.md, lines 105 ### Key observation 20% of PRs approved by StampHog in the July 28, 2026 report, at approximately $300 per month in tokens Metric · Reported · Medium confidence · `posthog-stamphog--key-metrics-2` Confidence reason: A linked first-party source states the claim. Qualifications: - Reported by: PostHog - Scope: PostHog PRs approved by StampHog and monthly token cost in the July 28, 2026 report - Denominator: PostHog PRs in the report's scope - Method: Company-reported production usage and token spend - Observation date: 2026-07 Evidence: - Supports · [2] [10,000 PRs a month is easy: How devex is evolving at PostHog](https://posthog.com/blog/10k-prs-a-month) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-2/content.md) · Preserved content.md, lines 131 ## Lessons and interpretation ### Lesson Use deterministic controls for known risks and allow the LLM to make approval stricter, never more permissive Inference · Catalog judgment · High confidence · `posthog-stamphog--lessons-learned-0` Confidence reason: The source code explicitly implements and documents this safety invariant. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, How it works ### Lesson Calibrate thresholds and deny categories from repository history rather than treating small diffs as inherently safe Inference · Catalog judgment · High confidence · `posthog-stamphog--lessons-learned-1` Confidence reason: The source code documents calibration against historical approval outcomes. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Tiers and Empirical basis ### Lesson Fail closed and preserve retry state when dependencies, credentials, or concurrent reviewer bots are unavailable Inference · Catalog judgment · High confidence · `posthog-stamphog--lessons-learned-2` Confidence reason: The source code explicitly documents fail-closed and retry behavior. Evidence: - Supports · [3] [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) · [Preserved copy](https://github.com/steel-experiments/internal-agents-map/blob/main/archive/sources/posthog-stamphog-source-3/content.md) · commit 988c9031bb93c74bafcdfb670c01497c79a4f644, tools/pr-approval-agent/README.md, Usage ## Sources 1. [Stop being the code review bottleneck](https://posthog.com/newsletter/code-review-tips) - Corporate article · First party · Evidence - Original URL: - Published: 2026-07-09 · Accessed: 2026-08-13 · Last verified: 2026-08-31 - Preserved copy in the repository: 2. [10,000 PRs a month is easy: How devex is evolving at PostHog](https://posthog.com/blog/10k-prs-a-month) - Engineering blog · First party · Evidence - Original URL: - Published: 2026-07-28 · Accessed: 2026-08-13 · Last verified: 2026-08-31 - Preserved copy in the repository: 3. [StampHog PR approval agent source code and documentation](https://github.com/PostHog/posthog/tree/988c9031bb93c74bafcdfb670c01497c79a4f644/tools/pr-approval-agent) - Source code · First party · Evidence - Original URL: - Accessed: 2026-08-13 · Last verified: 2026-08-31 - Preserved copy in the repository: