Add the per-unit fidelity vocabulary (inert) (#374, PR-A)

spec/fidelity-model.md

@@ -0,0 +1,44 @@
+# Fidelity Model
+
+How faithfully each carried unit must survive the carry, and how that is verified. This is a hub-only doc governing the carrying machinery ([`spec/files.json`][files], [`spec/files.schema.json`][files-schema], [`spec/audit.py`][audit]) and is not carried to the fleet. It is the companion to [`spec/scope-model.md`][scope-model]: scope decides *which* repos get a unit, fidelity decides *how faithfully* they must carry it.
+
+## The Fixed and the Overridable
+
+Carried content is a class with virtual functions. The **fixed** part is the interface - when a thing is invoked, what it is named, and where it is wired. The **overridable** part is the implementation body, which a repo replaces to fit its own targets. Validation must allow the override while detecting a change to the interface or to content meant to stay fixed. Integrity is by **content hash, never a version number** - a version stamp is a claim a repo can keep while editing the body, so it is never trusted for detection.
+
+## The Four Fidelity Levels
+
+Each [`spec/files.json`][files] entry declares one `fidelity`, defaulting to `presence`.
+
+- **presence** - the unit exists (a file, or a markdown section heading). The audit's baseline check.
+- **intent** - carried faithfully but judged by meaning, not bytes. A downstream copy legitimately differs (a governed divergence or a paraphrase), and equivalence is a human call via `intentRef`. The audit asserts nothing beyond presence.
+- **verbatim** - byte-identical to the hub's canonical after declared-placeholder normalization. The audit content-hashes the downstream copy against canonical. It applies to a whole file or a stable-handle region (a markdown section by heading, a workflow job by key).
+- **interface** - an overridable body that must honor a named contract. The audit checks the contract by name and wiring, never the body.
+
+Fidelity is a declared field defaulting to `presence`, never inferred from `whole`/`placeholders`. `.editorconfig` and `.markdownlint-cli2.jsonc` are both whole with no placeholders yet sit at opposite fidelity, because the discriminator is governance, not field shape.
+
+## Why Each Unit Sits Where It Does
+
+- **verbatim** - `.markdownlint-cli2.jsonc` (fleet-generic, no governed divergence), and the `github-release` job region of the release task (the canonical orchestration a repo must not fork).
+- **interface** - the release and PR workflows. Their fixed contract is the job and check names plus the artifact handoff, while the leaf build jobs are owned. See the override seam in [`AGENTS.md`][agents].
+- **intent** - `.editorconfig` and `.gitattributes` (the `[*] end_of_line` default and path pins vary by platform), `cspell.json` (the words list and file scope vary), `CODESTYLE.md` / `WORKFLOW.md` / `AUDIT.md` / `.github/copilot-instructions.md` (carried docs judged by meaning), and the ruleset payloads (whose live state is diffed separately).
+- **presence** - `README.md`, `HISTORY.md`, `.gitignore`, and the per-repo config that only needs to exist.
+
+## The Workflow Override Seam Contract
+
+The fixed interface of a workflow is stated in [`AGENTS.md`][agents] ("Orchestration vs. build - the override seam" and "Workflow YAML Conventions"), and the `interface` check enforces it by name and structure: the ruleset-bound required check `name: Check pull request workflow status job`, the `github-release` and `get-version` job keys, the `release-asset-<branch>-<target>` artifact-name handoff, and that `github-release` collects assets by `pattern:` / `merge-multiple:` and never by an `artifact-ids:` that names a build job's output. A repo owns the leaf `build-<target>-task` job list, its `needs` targets, and its paths-filter, and none of those are checked.
+
+## Placeholder Normalization
+
+A verbatim check normalizes only the tokens a unit **declares** in its `placeholders` list, never a blanket `<...>` regex. The declared tokens are literal strings (for example `<owner>`, `<repo>`, `<N>`), so masking touches exactly those and leaves intact the sibling metavariables a doc uses in prose (for example `<PATH>`, `<SHA>`). Line endings are neutralized before hashing, because EOL variance is governed by the line-ending rules, not a fidelity deviation.
+
+## Stale Versus Violated
+
+A verbatim mismatch is one of two things, told apart **by hash, not by a version**. The audit hashes each past revision of the hub's canonical from its own git history. If the downstream copy matches a **past** canonical revision, the base advanced and the copy is **stale** - re-vendor it. If it matches **no** revision the base ever produced, the repo **modified fixed content** - review it. A version stamp could claim to be current while being neither, so it is demoted to a human-facing label and never consulted for integrity.
+
+<!-- Repo -->
+[agents]: ../AGENTS.md
+[audit]: ./audit.py
+[files]: ./files.json
+[files-schema]: ./files.schema.json
+[scope-model]: ./scope-model.md

spec/files.json

@@ -1,28 +1,28 @@
 {
     "$schema": "./files.schema.json",
-    "note": "The standardization baseline: files and sections a fleet repo is expected to carry, and their intent authority. The audit checks presence (letter) and equivalence (intent); a section for an absent language or target is N/A. Each entry, and each section, carries an appliesTo selector - see spec/scope-model.md for the scope model and selector vocabulary.",
+    "note": "The standardization baseline: files and sections a fleet repo is expected to carry, and their intent authority. The audit mechanically checks presence (letter). Equivalence (intent) is judged by hand, and a section for an absent language or target is N/A. Each entry, and each section, carries an appliesTo selector - see spec/scope-model.md for the scope model and selector vocabulary. Each entry also has a fidelity (presence by default, or intent, verbatim, interface) governing how faithfully the content is checked - see spec/fidelity-model.md.",
     "baseline": [
-        { "path": "AGENTS.md", "sections": ["Repository Boundaries and Write Safety", "Git and Commit Rules", "Branching Model", "Release Model", { "name": "Operational Repositories", "appliesTo": ["operational"] }, "Pull Request Title and Commit Message Conventions", "Documentation Style Conventions", "Verification Discipline", "PR Review Etiquette", "Workflow YAML Conventions"], "intentRef": "AGENTS.md", "appliesTo": "*" },
-        { "path": "CODESTYLE.md", "whole": true, "placeholders": ["InternalsVisibleTo project names"], "intentRef": "CODESTYLE.md", "appliesTo": "*" },
-        { "path": "WORKFLOW.md", "whole": true, "intentRef": "WORKFLOW.md", "appliesTo": "*" },
+        { "path": "AGENTS.md", "fidelity": "intent", "sections": ["Repository Boundaries and Write Safety", "Git and Commit Rules", "Branching Model", "Release Model", { "name": "Operational Repositories", "appliesTo": ["operational"] }, "Pull Request Title and Commit Message Conventions", "Documentation Style Conventions", "Verification Discipline", "PR Review Etiquette", "Workflow YAML Conventions"], "intentRef": "AGENTS.md", "appliesTo": "*" },
+        { "path": "CODESTYLE.md", "fidelity": "intent", "whole": true, "placeholders": ["InternalsVisibleTo project names"], "intentRef": "CODESTYLE.md", "appliesTo": "*" },
+        { "path": "WORKFLOW.md", "fidelity": "intent", "whole": true, "intentRef": "WORKFLOW.md", "appliesTo": "*" },
         { "path": "README.md", "appliesTo": "*" },
         { "path": "HISTORY.md", "appliesTo": "*" },
-        { "path": ".github/copilot-instructions.md", "whole": true, "placeholders": ["<owner>", "<repo>", "<N>"], "appliesTo": "*" },
-        { "path": ".editorconfig", "whole": true, "intentRef": "AGENTS.md#line-endings", "appliesTo": "*" },
-        { "path": ".gitattributes", "whole": true, "intentRef": "AGENTS.md#line-endings", "appliesTo": "*" },
-        { "path": ".markdownlint-cli2.jsonc", "whole": true, "appliesTo": "*" },
-        { "path": "cspell.json", "whole": true, "appliesTo": "*" },
+        { "path": ".github/copilot-instructions.md", "fidelity": "intent", "whole": true, "placeholders": ["<owner>", "<repo>", "<N>"], "appliesTo": "*" },
+        { "path": ".editorconfig", "fidelity": "intent", "whole": true, "intentRef": "AGENTS.md#line-endings", "appliesTo": "*" },
+        { "path": ".gitattributes", "fidelity": "intent", "whole": true, "intentRef": "AGENTS.md#line-endings", "appliesTo": "*" },
+        { "path": ".markdownlint-cli2.jsonc", "fidelity": "verbatim", "whole": true, "appliesTo": "*" },
+        { "path": "cspell.json", "fidelity": "intent", "whole": true, "appliesTo": "*" },
         { "path": ".gitignore", "appliesTo": "*" },
-        { "path": "version.json", "intentRef": "WORKFLOW.md#d3---versioning-and-classification", "appliesTo": "*" },
-        { "path": "repo-config/develop.json", "intentRef": "repo-config/README.md", "appliesTo": ["release"] },
-        { "path": "repo-config/operational/develop.json", "intentRef": "repo-config/README.md", "appliesTo": ["operational"] },
-        { "path": "repo-config/main.json", "intentRef": "repo-config/README.md", "appliesTo": "*" },
-        { "path": "AUDIT.md", "intentRef": "docs/repo-config-carry.md", "appliesTo": "*" },
-        { "path": "spec/secrets.json", "intentRef": "docs/repo-config-carry.md", "appliesTo": "*" },
+        { "path": "version.json", "fidelity": "intent", "intentRef": "WORKFLOW.md#d3---versioning-and-classification", "appliesTo": "*" },
+        { "path": "repo-config/develop.json", "fidelity": "intent", "intentRef": "repo-config/README.md", "appliesTo": ["release"] },
+        { "path": "repo-config/operational/develop.json", "fidelity": "intent", "intentRef": "repo-config/README.md", "appliesTo": ["operational"] },
+        { "path": "repo-config/main.json", "fidelity": "intent", "intentRef": "repo-config/README.md", "appliesTo": "*" },
+        { "path": "AUDIT.md", "fidelity": "intent", "intentRef": "docs/repo-config-carry.md", "appliesTo": "*" },
+        { "path": "spec/secrets.json", "fidelity": "intent", "intentRef": "docs/repo-config-carry.md", "appliesTo": "*" },
         { "path": ".github/dependabot.yml", "appliesTo": "*" },
         { "path": ".vscode/tasks.json", "sections": ["clean-compile task group"], "reference": "catalog/snippets/configs/vscode-tasks.json", "appliesTo": ["csharp"] },
         { "path": ".vscode/tasks.json", "sections": ["clean-compile task group"], "reference": "catalog/snippets/configs/vscode-tasks-python.json", "appliesTo": ["python"] },
-        { "path": "codecov.yml", "reference": "catalog/snippets/configs/codecov.yml", "intentRef": "WORKFLOW.md", "appliesTo": ["csharp", "python"] },
+        { "path": "codecov.yml", "fidelity": "intent", "reference": "catalog/snippets/configs/codecov.yml", "intentRef": "WORKFLOW.md", "appliesTo": ["csharp", "python"] },
         { "path": ".dockerignore", "appliesTo": ["docker"] },
         { "path": "Docker/README.md", "reference": "catalog/snippets/configs/docker-hub-readme.md", "appliesTo": ["docker"] }
     ]

spec/files.schema.json

@@ -36,7 +36,20 @@
                     "placeholders": { "type": "array", "items": { "type": "string" } },
                     "reference": { "type": "string" },
                     "intentRef": { "type": "string" },
-                    "appliesTo": { "type": ["string", "array"], "items": { "type": "string" }, "minItems": 1 }
+                    "appliesTo": { "type": ["string", "array"], "items": { "type": "string" }, "minItems": 1 },
+                    "fidelity": { "enum": ["presence", "intent", "verbatim", "interface"] },
+                    "contract": {
+                        "type": "object",
+                        "additionalProperties": false,
+                        "properties": {
+                            "requiredJobKeys": { "type": "array", "items": { "type": "string" } },
+                            "requiredCheckName": { "type": "string" },
+                            "artifactNameToken": { "type": "string" },
+                            "requireTokensInJob": { "type": "object", "additionalProperties": { "type": "array", "items": { "type": "string" } } },
+                            "forbidTokensInJob": { "type": "object", "additionalProperties": { "type": "array", "items": { "type": "string" } } },
+                            "verbatimJobs": { "type": "array", "items": { "type": "string" } }
+                        }
+                    }
                 }
             }
         }

spec/validate.py

@@ -18,6 +18,10 @@
 WORKFLOW_MODELS = ("release", "operational")
 RELEASE_TRIGGERS = ("two-phase", "publish-on-merge", "dispatch-only", "none")
 CONSUMER_MODELS = ("push", "pull")
+# How faithfully a carried unit is checked (spec/fidelity-model.md). Default presence.
+FIDELITIES = ("presence", "intent", "verbatim", "interface")
+# The keys an interface unit's `contract` may carry (kept in sync with files.schema.json).
+CONTRACT_KEYS = {"requiredJobKeys", "requiredCheckName", "artifactNameToken", "requireTokensInJob", "forbidTokensInJob", "verbatimJobs"}
 
 
 def load(rel):
@@ -226,6 +230,37 @@ def check_selector(where, applies_to):
             continue
         path = item.get("path", "?")
         check_selector(path, item.get("appliesTo", "*"))
+
+        # fidelity governs how faithfully the unit is checked (spec/fidelity-model.md). CI runs no schema
+        # validation, so shape-check the fidelity fields here rather than let a malformed contract or an
+        # outside-root reference slip through and crash a later check.
+        fid = item.get("fidelity", "presence")
+        if fid not in FIDELITIES:
+            errors.append(f"files.json: {path} fidelity '{fid}' invalid (expected one of {', '.join(FIDELITIES)})")
+        has_contract = "contract" in item
+        if has_contract and fid != "interface":
+            errors.append(f"files.json: {path} has a contract but fidelity is '{fid}' (contract is only for fidelity 'interface')")
+        if fid == "interface" and not has_contract:
+            errors.append(f"files.json: {path} fidelity 'interface' requires a contract")
+        if has_contract:
+            contract = item["contract"]
+            if not isinstance(contract, dict):
+                errors.append(f"files.json: {path} contract must be an object")
+            else:
+                unknown = set(contract) - CONTRACT_KEYS
+                if unknown:
+                    errors.append(f"files.json: {path} contract has unknown key(s): {', '.join(sorted(unknown))}")
+        ref = item.get("reference")
+        if ref is not None and not isinstance(ref, str):
+            errors.append(f"files.json: {path} reference must be a string")
+            ref = None
+        elif isinstance(ref, str) and (ref.startswith("/") or ".." in pathlib.PurePosixPath(ref).parts):
+            errors.append(f"files.json: {path} reference '{ref}' must be a repo-relative path (no leading / or ..)")
+        if fid == "verbatim":
+            src = ref if isinstance(ref, str) else path
+            if isinstance(src, str) and not (ROOT / src).exists():
+                errors.append(f"files.json: {path} fidelity 'verbatim' but its canonical source {src} is missing")
+
         sections = item.get("sections", [])
         if not isinstance(sections, list):
             errors.append(f"files.json: {path} sections must be an array")