Provider packages translate a shared agent loop into model-specific request, cache, and session behavior.
Agent Atlas / Coding agents
earendil-works/pi
A compact, extensible coding-agent stack whose package boundaries and session model make provider behavior, compaction, rendering, and customization legible.
Coding agent
Full dossier
Reported + sourced
Reviewed August 26, 2026
Intended operator
Developers who want a programmable terminal agent and reusable agent packages.
Primary surfaces
terminal coding agent / agent packages / extensions
Tracked repository
Teaching mechanism
Session affinity is evidence, not one reusable header
Provider-specific session identifiers and expiry behavior are kept in typed session state instead of being flattened into one generic transport assumption.
Evidence limitTyped session state does not prove that every provider preserves continuity under every failure.
Inspect the source
System Map
Eight inspection boundariesConversation entries, compaction records, and provider session metadata remain distinct forms of state.
The agent package exposes tools and extensions while the terminal client owns interaction and rendering.
Tool availability and host authority remain deployment choices that extensions must make visible.
Durable session entries, compaction records, and affinity metadata preserve resumable work.
Delegation is not the primary teaching surface; package composition and session continuity are better-evidenced boundaries.
The terminal renders durable evidence, cache pressure, and session state for operator inspection.
Typed entries, rendered session artifacts, tests, and package boundaries provide the strongest receipts.
Learn Through This Project
8 lessons
Chapter 1
Before the First Model Request
Chapter 2
The Invisible Prompt
Chapter 3
Tool Calls: Contract, Authorization, Execution
Chapter 4
Loops, Workflows, and Recovery
Chapter 6
Memory Is a Typed Storage Contract
Chapter 8
The Human Control Loop
Chapter 9
Trust Must Make Its Case
Chapter 10
The Future Has Three Branches
Latest Reporting
8 articles
Pi's New Harness Writes the Restart Point Before It Acts
August 20, 2026 — Pi's dev branch is turning an agent run into a durable, remotely attachable session—but its most important promise is also the simplest: record the restart point before the model or tool gets to act. earendil-works/pi
API Discovery: Pi’s xAI Route Keeps Reasoning State in PlayAugust 17, 2026 — Pi now sends every built-in xAI model through the Responses API—a useful route for agents that need a deliberate, client-owned continuity plan rather than a model-name swap. earendil-works/pi
API Discovery: Pi converts strict tool schemas at the provider boundaryAugust 12, 2026 — Pi’s public constrained-sampling API now has a fresher compatibility layer for builders who want strict tool calls without permanently rewriting the schema their application owns. earendil-works/pi
The Harness Was Taking the Test TooJuly 30, 2026 — OpenAI says two context choices lifted GPT-5.6 Sol from 13.3% to 38.3% on the ARC-AGI-3 public set. Codex source shows those “settings” are really a production memory system—and rival harnesses reveal how much of it can be copied. openai/codex, pydantic/pydantic-ai, earendil-works/pi, NousResearch/hermes-agent, mistralai/mistral-vibe, anomalyco/opencode, QwenLM/qwen-code, google-gemini/gemini-cli, cline/cline, aaif-goose/goose, OpenHands/OpenHands
Builder Work: Pi Counts the Work Its Agent HidesJuly 21, 2026 — Pi's latest accounting patch treats compaction, branch summaries, and tool-result hooks as model work with receipts—not invisible overhead beneath an agent's final answer. earendil-works/pi
The Hard Part of an Agent Protocol Rewrite Is YesterdayJuly 17, 2026 — Tau is replacing its legacy agent protocol with Pi-compatible shapes, but its more consequential promise sits at the JSONL boundary: old sessions are meant to cross without pretending the old runtime still exists. alejandro-ao/tau, earendil-works/pi
Tau's Protocol Rewrite Keeps Yesterday's SessionsJuly 17, 2026 — Tau is choosing Pi-compatible extension and event shapes, but its public migration code makes a more human promise: a user's old session should have a route into the new system. alejandro-ao/tau, earendil-works/pi
Pi Stops Treating Session Affinity as One HeaderJuly 15, 2026 — Pi’s OpenRouter fix shows why “OpenAI-compatible” requests still need provider-specific routing details. earendil-works/pi
Primary Sources
Open Questions
- Which host permissions and extension effects can a shared session prove after the fact?
Evidence state describes what this Atlas profile can support today. It is not a product score and it is not evidence that uninspected capabilities are absent.