# Mycelium > de-novo Mycelium — the facts under the forest. One append-only log of assertions per project: what is held true, since when, with what confidence, in which domain, on whose word. Workers propose; a person or the judging worker commits or invalidates; readers query a moment. Use when work produces a fact that outlives the seat that found it (a locked decision, a verified cause, a blocker, a check result), when a person asks what the project currently holds true, or when the user runs /mycelium. Values live in .agents/mycelium.yml (domains, entity types, predicates with one|many cardinality, and the judges who may commit; tracked). Corrections are amendments that point back; nothing is edited in place. The CLI never judges; the promotion is yours. - Skill: `de-novo/mycelium` (Agent Skill, multi-file: 5 files) - Install (CLI): `npx skillmds@latest add de-novo/mycelium` - Raw SKILL.md: https://api.skillmd.com/api/skills/de-novo/mycelium/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Docs & Writing - Author: de-novo (https://skillmd.com/u/de-novo) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/de-novo/mycelium --- # Mycelium Forester's graph is the work: items, dependencies, claims. It says nothing about what the work found out. Mycelium is the other graph, the one under the forest: facts with time, confidence, domain, and provenance attached, so a worker seated tomorrow starts from what was proven today instead of from the chat that proved it. This file owns the pattern. The envelope, the transitions, the query, and the CLI are in [references/log.md](references/log.md). Forester pattern: [forester](../forester/SKILL.md). Seats: [dryad](../dryad/SKILL.md). ## Two graphs, one seam | Graph | Node | Owner | Home | | --- | --- | --- | --- | | Forester | an item of work and its state | the plan | `.agents/forester-plan.yml` | | Mycelium | an assertion and its status | the log | `/mycelium/.jsonl` | The seam is one direction only: a seat's done or blocked report may be proposed as a fact (`propose --from-seat`, `--report blocked` for the latter). Mycelium never changes the plan, never assigns, never marks an item done. ## The rule **Propose is cheap; commit is a judgement.** Any worker may propose, and a proposal is only staging. Only a judge commits: a person, or the worker the project names in `judges`. A project that names no judges is permissive, and `status` says so; an unattended run wants `judges` and `mode: restricted`, never a worker naming itself judge. A committed fact that stops being true is invalidated, never deleted: the log keeps what was held and for how long. **Wrong is amended; no longer true is invalidated.** A fact you got wrong gets a corrected copy (`amend`), and the original is closed as if it never held. A fact that was true and stopped is invalidated or superseded, and the moment it held stays answerable. Nothing is ever edited in place. **Every line names its writer.** A seat standing in its own worktree is `seat:` without saying so; a person or a judging agent passes `--by`. The id is a declaration the project trusts, not a login; the reference says what that means on a shared machine. ## Write When your work produces a fact worth keeping: 1. **Ask whether it outlives you.** A locked decision, a verified cause, a dependency between lanes, a blocker, a check's pass or fail, an approach tried and failed: yes. A file hunk, a build log, a heartbeat, a chat turn: no. The full list is the reference's commit rules. 2. **Propose it in the envelope.** Subject, predicate, object, the subject's type, the domain, the source you read it from, and your confidence. The domain, the types, and the predicate must already be in `.agents/mycelium.yml`; if the vocabulary lacks one, say so to a person rather than inventing it. A predicate is `one` when a subject holds a single object at a time (a cause, a definition of done) and `many` when it holds several (a dependency, a blocker, an owner). 3. **Name the source precisely.** A file path and line, a PR, a seat's report, a check's output line, and the commit you read it at (`--ref-commit`; `--from-seat` names the seat's own head). A fact with no source is a rumour and is not proposed; a fact with a commit can be told from one the baseline has moved past. 4. **Correct with `amend`, not with a second proposal.** If you find your own proposal wrong, or another's, amend it and say why in the source. The log then shows the correction as one link, not two unrelated facts. 5. **Do not commit your own proposal** unless the project names you as its judge. Say what you proposed in your seat report. ## Judge When you hold the judge's role, or are a person reading staging: 1. `query --status staging` and read each candidate against its source. 2. Commit what is true. A conflict with an active fact on the same subject and predicate is refused; supersede only when the newer fact replaces the older, and say so. 3. Invalidate with a reason a stranger can read. `--below 0.5` finds the candidates least sure of themselves; those get a source check first. ## Read Ask the log, not the chat. `query --domain ` for what is held now, `query --at ` for what was held then, `query --s --all` for one thing's history, `query --since ` when you come back to a seat and want only what changed, `trace ` for how a fact got to be what it is. Put the answer into the worker's brief with `query --brief`, so the brief stays short and the facts stay in one home. ## Invariants — not weakenable - **The log is append-only.** No edit, no delete. Invalidation is a new line. - **The graph is the fold of the log.** Nothing else is consulted. - **Every assertion names its source and its agent.** No defaults for either. - **Correction is a new line that points back.** `amend` links; nothing is edited. - **Vocabulary is declared, not discovered.** Unknown domains, types, and predicates are refused. - **A write is one step.** Every write re-reads the log under a lock; no two writers pass the same check on a stale graph. - **The CLI never calls a model and never judges.** Commit is a person's or the named judge's. - **Mycelium does not write the plan.** The Forester seam reads seats; it does not touch them. ## Not this skill - Deciding the work or its order. Forester. - Seating, reporting, or finishing a worker. Dryad. - A document a person reads. Understory can point at assertion ids. - A second store per machine, a query language, a merge across machines. Those are named as later work in the design note and are not here.