fix(skill-memory): accept plain filesystem path in skill provenance (opencode #33580)

opencode's skill tool changed the 'Base directory for this skill:' line from a
file:// URL to a plain filesystem path (upstream #33580). Our parser hard-required
file:/// so parseSkillProvenance returned null on current opencode -> skill-load
registry never populated -> every agent ctx_skill_note failed with a provenance
parse error. Agent-written notes silently stopped 2026-07-02 (only historian-path
notes, which bypass this parser, continued).

Widen BASE_DIR_REGEX to capture the rest of the line and branch on the value:
file:// -> fileURLToPath (legacy/back-compat); otherwise treat as a plain path.
Keeps the line-anchor + last-match decoy-rejection invariant. +4 regression tests
(plain global, plain project, plain decoy last-match, plain mid-line-ignore); all
existing file:// tests unchanged.

Author: Tehan

packages/plugin/src/features/magic-context/skill-memory/provenance.test.ts

@@ -91,4 +91,36 @@ describe("parseSkillProvenance", () => {
         const result = parseSkillProvenance(output, "right");
         expect(result!.resolvedPath).toBe(`${HOME}/.config/opencode/skills/right/SKILL.md`);
     });
+
+    test("parses a PLAIN filesystem path (opencode #33580 — no file:// prefix)", () => {
+        const output = `# Skill: council\nsome content\nBase directory for this skill: ${HOME}/.config/opencode/skills/council`;
+        const result = parseSkillProvenance(output, "council");
+        expect(result).not.toBeNull();
+        expect(result!.resolvedPath).toBe(`${HOME}/.config/opencode/skills/council/SKILL.md`);
+        expect(result!.tier).toBe("global");
+        expect(result!.skillSource).toBe("opencode-global");
+    });
+
+    test("parses a PLAIN filesystem path for a PROJECT skill", () => {
+        const output = `Base directory for this skill: ${HOME}/projects/foo/.opencode/skills/my-skill`;
+        const result = parseSkillProvenance(output, "my-skill");
+        expect(result!.tier).toBe("project");
+        expect(result!.skillSource).toBe("opencode-project");
+    });
+
+    test("takes the LAST match with a plain-path decoy followed by the real plain line", () => {
+        const output =
+            `# Skill: skill-memory internals\n` +
+            `Example: Base directory for this skill: /decoy/evil\n` +
+            `more prose\n` +
+            `Base directory for this skill: ${HOME}/.config/opencode/skills/real`;
+        const result = parseSkillProvenance(output, "real");
+        expect(result!.resolvedPath).toBe(`${HOME}/.config/opencode/skills/real/SKILL.md`);
+    });
+
+    test("ignores a mid-line (non-line-anchored) plain-path mention", () => {
+        const output = `Note: see Base directory for this skill: /wrong/x for details.\nBase directory for this skill: ${HOME}/.config/opencode/skills/right`;
+        const result = parseSkillProvenance(output, "right");
+        expect(result!.resolvedPath).toBe(`${HOME}/.config/opencode/skills/right/SKILL.md`);
+    });
 });

packages/plugin/src/features/magic-context/skill-memory/provenance.ts

@@ -8,31 +8,35 @@ export interface SkillProvenance {
     loadedAt: number;
 }
 
-// Matches: "Base directory for this skill: file:///abs/path/to/skill/dir"
-// Uses fileURLToPath (not naive regex capture) for cross-platform correctness.
-// Anchored to line-start (`^…/gm`) AND we take the LAST match: opencode appends
-// this provenance line at the END of the tool output, so if the skill's own
-// CONTENT contains the same phrase (e.g. a skill documenting skill-memory
-// provenance), a first-match/unanchored parse would capture the wrong URL and
-// misdirect recall to a bogus skill identity. Line-anchoring rejects mid-prose
-// mentions; last-match ensures the real trailing provenance line wins even if an
-// example block reproduces it at column 0.
-const BASE_DIR_REGEX = /^Base directory for this skill: (file:\/\/\/[^\n\r]+)/gm;
+// Matches: "Base directory for this skill: <path-or-file-url>"
+// opencode #33580 changed the emit from a file:// URL to a PLAIN filesystem
+// path, so we accept BOTH forms. Anchored to line-start (^…/gm) + last-match:
+// opencode appends this provenance line at the END of the tool output, so if
+// the skill's own CONTENT contains the phrase at column 0, last-match ensures
+// the real trailing line wins; line-anchoring rejects mid-prose mentions.
+const BASE_DIR_REGEX = /^Base directory for this skill: (.+)$/gm;
 
 export function parseSkillProvenance(output: string, skillId: string): SkillProvenance | null {
     const matches = [...output.matchAll(BASE_DIR_REGEX)];
     if (matches.length === 0) return null;
 
-    const fileUrl = matches[matches.length - 1][1].trim();
+    const raw = matches[matches.length - 1][1].trim();
+    if (!raw) return null;
+
     let absDir: string;
-    try {
-        // Normalize OS-native separators to forward slashes: on Windows
-        // fileURLToPath yields backslash paths, which would fail the
-        // forward-slash startsWith/includes tier/source checks below and
-        // misclassify global skills as project-local.
-        absDir = fileURLToPath(new URL(fileUrl)).replace(/\\/g, "/");
-    } catch {
-        return null;
+    if (raw.startsWith("file://")) {
+        // Legacy opencode (pre-#33580) emitted a file:// URL. Use fileURLToPath
+        // (not naive slice) for cross-platform + percent-decoding correctness.
+        try {
+            absDir = fileURLToPath(new URL(raw)).replace(/\\/g, "/");
+        } catch {
+            return null;
+        }
+    } else {
+        // Current opencode (#33580) emits a plain filesystem path. Normalize
+        // OS-native backslashes to forward slashes so the tier/source
+        // startsWith/includes checks below match on every platform.
+        absDir = raw.replace(/\\/g, "/");
     }
 
     const resolvedPath = `${absDir}/SKILL.md`;