Autostart: the three ways the skill gets loaded

Loading is not acting. Once loaded, the skill does nothing in a project that has no .keep-the-why unless a developer explicitly asks to set it up (setup.md, "Detection and the two independent wizards") — so every start path below either gates on that file or is the developer asking. What a start path decides is only whether the skill is in the session at all before the first request, instead of hoping the agent's own skill discovery matches the conversation against SKILL.md's description.

Referenced by setup.md's wizard (the start-path question and step 2), not a mandate. Each entry states what was actually verified and how, so "listed here" never gets mistaken for "guaranteed to work for you". Growing and incomplete by design — a pull request adding a verified example for a tool that isn't here yet is welcome any time; for anything else, open a new issue.

The three start paths

Every session, machine-wide — a developer sets it up once, on their own machine, for every project they work in: the agent's session-start mechanism (a hook, a startup rule) checks for .keep-the-why and, if present, tells the agent to load the skill before anything else. Gated on the file on purpose: an unconditional load would put SKILL.md into the context of every session in every project, including ones that never opted in, for nothing. Personal, not committed — a collaborator on the same project gets nothing from it.
The project asks — committed with the project, so every collaborator and every session benefits. Two forms, usable together:
a project-scoped session hook, where the agent tool has one (Claude Code: .claude/settings.json);
a "Keep the Why" section in the project's entry-point file (AGENTS.md, with CLAUDE.md importing it) telling any agent that reads that file to load the skill first. Tool-neutral, and the right form for a vendored, pinned skill (setup.md, "Pinned versions"): the section points at the exact SKILL.md the project committed.
The developer asks — nothing to set up. Name the skill, or point the agent at SKILL.md and say "follow it". This is how the eval suite hands the skill to every agent tool other than Claude Code (docs/evals.md, docs/agent-matrix.md), so it is verified on all of them by construction.

They combine: a developer with path 1 working on a project with path 2 gets told twice, which is harmless — the skill's setup check runs once per session either way.

The entry-point section (path 2, tool-neutral)

Paste into the project's AGENTS.md (or whatever entry-point file the project already uses). If the agent tool reads CLAUDE.md instead — Claude Code does, and does not read AGENTS.md on its own — a root CLAUDE.md containing just @AGENTS.md imports it; most projects already have that line. Adjust the SKILL.md path to where the project keeps the skill (pinned-path in .keep-the-why when pinned, otherwise the install location the project's agents use).

## Keep the Why

This project records the reasoning behind its code with the Keep the Why
skill (https://keepthewhy.com) — the `.keep-the-why` file at the project
root is its config. Before doing anything else in a session, whatever the
first request is about, load the skill: in Claude Code, invoke the
`keep-the-why` skill (Skill tool); in any other agent, read
`.claude/skills/keep-the-why/SKILL.md` and follow it, including the
`references/*.md` files it points to for the situation at hand.

This is the one exception to setup.md's rule that nothing about Keep the Why goes into the entry-point file: the project chose this start path, so the section is the project's own editorial decision, written by the wizard only when asked for.

Claude Code

Path 1 — every session, machine-wide. The hook script below, saved in ~/.claude/settings.json (user scope) instead of the project. Same mechanism as the project-scoped hook; in real daily use, not separately eval-verified.

Path 2, hook — the project asks. The same script as a project-scoped SessionStart hook in .claude/settings.json, checked into the repo. It checks for the project's .keep-the-why — or, for a project not yet migrated, the legacy  marker in AGENTS.md — before injecting anything, so it stays silent on projects that don't use Keep the Why rather than firing unconditionally on every session.

{
  "hooks": {
    "SessionStart": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "found=\"\"; if [ -f .keep-the-why ]; then found=1; fi; if [ -z \"$found\" ] && [ -f AGENTS.md ] && grep -q '<!-- keep-the-why:config -->' AGENTS.md 2>/dev/null; then found=1; fi; if [ -z \"$found\" ]; then for f in */.keep-the-why; do if [ -f \"$f\" ]; then found=1; break; fi; done; fi; if [ -z \"$found\" ]; then for f in */AGENTS.md; do if [ -f \"$f\" ] && grep -q '<!-- keep-the-why:config -->' \"$f\" 2>/dev/null; then found=1; break; fi; done; fi; if [ -n \"$found\" ]; then echo '{\"hookSpecificOutput\":{\"hookEventName\":\"SessionStart\",\"additionalContext\":\"This project uses the keep-the-why skill (a .keep-the-why config file exists, or AGENTS.md still carries a legacy keep-the-why:config block). Invoke the keep-the-why skill (Skill tool) now, before doing anything else in this session, whatever the first request is about.\"}}'; fi; exit 0"
          }
        ]
      }
    ]
  }
}

The command field, unescaped for readability — functionally identical:

found=""
if [ -f .keep-the-why ]; then
  found=1
fi
if [ -z "$found" ] && [ -f AGENTS.md ] && grep -q '<!-- keep-the-why:config -->' AGENTS.md 2>/dev/null; then
  found=1
fi
if [ -z "$found" ]; then
  for f in */.keep-the-why; do
    if [ -f "$f" ]; then
      found=1
      break
    fi
  done
fi
if [ -z "$found" ]; then
  for f in */AGENTS.md; do
    if [ -f "$f" ] && grep -q '<!-- keep-the-why:config -->' "$f" 2>/dev/null; then
      found=1
      break
    fi
  done
fi
if [ -n "$found" ]; then
  echo '{"hookSpecificOutput":{"hookEventName":"SessionStart","additionalContext":"This project uses the keep-the-why skill (a .keep-the-why config file exists, or AGENTS.md still carries a legacy keep-the-why:config block). Invoke the keep-the-why skill (Skill tool) now, before doing anything else in this session, whatever the first request is about."}}'
fi
exit 0

Checks the project root and one level of subdirectories for either marker; adjust the two for f in */... loops for a different layout. A project still on the previous, AGENTS.md-embedded config location (not yet migrated, see references/migrations.md) is matched through the legacy marker on purpose: the skill then loads and runs the migration itself, instead of the session silently treating a project that already opted in as one that never did — exactly the failure the eval case config-migrates-to-dedicated-file kept reproducing while the hook only knew the new location.

Evidence (hook): the eval suite's _base fixture carries exactly this hook (tools/evals/fixtures/_base/.claude/settings.json). Re-running the 10 (of 11) activation-gap failures from the 2026-08-25 full run that could have one went from 0/10 invoking the Skill tool to 10/10; 9/10 passed outright, and the one holdout traced to an unrelated fixture bug (all 10 pass since that fix). Full writeup: docs/evals.md, PR #190. The legacy-marker branch was carried by the user-scoped variant first and folded back into the documented script in 2026-09.

Path 2, entry-point section — the project asks. The section above in AGENTS.md, plus a root CLAUDE.md containing @AGENTS.md (Claude Code reads CLAUDE.md, not AGENTS.md). Skill installed or vendored at .claude/skills/keep-the-why/.

Evidence (entry-point section): eval case autostart-project-instruction-loads-skill — the _base fixture with the hook removed, the section in AGENTS.md, CLAUDE.md importing it, and a plain code question as the prompt ("why does the retry logic look so defensive?") that never names the skill. 2026-09-04, Claude Code 2.1.259, Claude Sonnet 5: 3 of 3 runs invoked the Skill tool as the very first action. Control — same fixture and prompt with the section removed and still no hook: 0 of 3 loaded the skill. Same-day measurement, so the difference is the section and nothing else.

Path 3 — the developer asks. /keep-the-why, or naming the skill in the request. Nothing to set up.

Hermes Agent

Hermes injects AGENTS.md (and CLAUDE.md) from the working directory into the session on its own — its "rules" mechanism, disabled by --ignore-rules — so the entry-point section (path 2) works as written, no import line needed.

Evidence: one live run, 2026-09-04, hermes chat with Claude Sonnet 5 via OpenRouter, terminal and file toolsets, on the same fixture the Claude Code eval case uses (hook removed, section in AGENTS.md), same code question. First recorded reasoning: "AGENTS.md says I should load the keep-the-why skill before doing anything else"; first file read: .claude/skills/keep-the-why/SKILL.md. A single run checked by hand, not an eval measurement — the eval runner's Hermes driver hands the skill over explicitly (path 3) and so can't measure this path.

Whether Hermes has a session-start hook usable for path 1 wasn't checked. Path 3: hermes chat -q "Read ./skills/keep-the-why/SKILL.md and follow it. <request>" — the eval suite's own mode for this agent.

Codex CLI

Codex reads AGENTS.md from the working directory on its own, so the entry-point section (path 2) works as written, no import line needed.

Evidence: eval case autostart-project-instruction-loads-skill, run with the Codex CLI driver and the prompt sent bare (no "read SKILL.md" prefix; the skill at .claude/skills/keep-the-why/, where the section points). 2026-09-05, codex-cli 0.149.0, Claude Sonnet 5 via OpenRouter: 3 of 3 runs read SKILL.md unprompted, as the first or second tool call (the other being a look at .keep-the-why). Control — same fixture and prompt, section removed: 1 of 3 read it, as the seventh call, while exploring the tree after the question was already answered — that is curiosity, not the project asking.

Whether Codex has a session-start hook usable for path 1 wasn't checked. Path 3: the eval suite's own mode for this agent.

opencode

opencode reads AGENTS.md on its own and, beyond that, has a native skill tool that discovers .claude/skills/ — so with the section in place it doesn't read SKILL.md by hand, it invokes the skill the way Claude Code does.

Evidence: the same eval case, same fixture and bare prompt, opencode driver. 2026-09-05, opencode 1.18.22, Claude Sonnet 5 via OpenRouter: 3 of 3 runs invoked skill: keep-the-why as the very first tool call. Control without the section: 0 of 3 loaded it in any form — the native discovery alone does not make the skill load; the project has to ask.

Path 1 not checked. Path 3: the eval suite's own mode.

Cline

Cline picks up AGENTS.md from the working directory as project rules, so the section works as written.

Evidence: the same eval case, same fixture and bare prompt, Cline driver. 2026-09-05, Cline 3.0.61, Claude Sonnet 5 via OpenRouter: 3 of 3 runs read .claude/skills/keep-the-why/SKILL.md unprompted, as the first or second tool call. Control without the section: 0 of 3.

Path 1 not checked. Path 3: the eval suite's own mode.

Other agents

Path 2, entry-point section: should work on any agent that reads AGENTS.md (or its own equivalent) at session start — that is the whole point of the file — but it is instruction-following, not a hook, and it is verified above only for Claude Code, Codex CLI, opencode and Cline (eval, 3 of 3 each against a 0 or 1 of 3 control) and Hermes (one live run). If you've checked it on Kimi Code, oh-my-pi, Pi, Gemini CLI or anything else, a pull request adding what you saw is exactly the kind of contribution this file wants.
Path 1 and project-scoped hooks: whether an agent has a session-start mechanism at all, and what it looks like, only that agent's own documentation knows; nothing is listed here until someone has run it.
Path 3: verified on Cline, Codex CLI, Hermes, Kimi Code, oh-my-pi, opencode and Pi — it is how the eval suite and the agent & model matrix hand the skill to every one of them.

Hit a problem, or have something to report that isn't a ready-made example? Open a new issue rather than commenting on a closed one.