feat: structured findings contract (machine-readable gadfly-findings block) (#16)

Co-authored-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>
Co-committed-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>

cmd/gadfly/consolidate.go

@@ -28,6 +28,22 @@ func (v verdict) label() string {
 	}
 }
 
+// severity maps a verdict to a canonical severity word (the same vocabulary as
+// the structured findings: critical/high/medium/small/trivial). Used as the
+// raw_severity for heuristic-scraped findings, which carry no per-finding
+// severity of their own — so the telemetry store sees one consistent vocabulary
+// instead of a mix of canonical words and full verdict phrases.
+func (v verdict) severity() string {
+	switch v {
+	case verdictBlocking:
+		return "high"
+	case verdictMinor:
+		return "small"
+	default:
+		return "trivial"
+	}
+}
+
 // parseVerdict extracts a specialist's self-reported verdict from its output.
 // The base prompt tells each lens to lead with one of the three phrases.
 func parseVerdict(out string) verdict {
@@ -100,7 +116,9 @@ func renderConsolidated(results []specialistResult) string {
 		headline, len(results), strings.Join(specialistNames(results), ", "))
 
 	for _, r := range results {
-		body := strings.TrimSpace(r.out)
+		// Strip the machine-readable ```gadfly-findings block — it's for tooling
+		// (telemetry/consolidation), not for human readers of the comment.
+		body := strings.TrimSpace(stripFindingsBlock(r.out))
 		if body == "" {
 			body = "_(no output)_"
 		}

cmd/gadfly/emit.go

@@ -10,11 +10,14 @@ package main
 //     the review markdown consumed by run.sh) and never changes the exit code.
 //   - It depends only on the Go stdlib (net/http).
 //
-// Findings are extracted heuristically from each lens's markdown: a "path:line"
-// reference (e.g. run/executor.go:166) anchors a finding, whose title is the
-// nearest preceding markdown heading / numbered item / bold lead-in (else the
-// first sentence of the finding's paragraph). This is best-effort signal for the
-// store to aggregate — not a structured contract the reviewer guarantees.
+// Findings come PRIMARILY from each lens's machine-readable ```gadfly-findings
+// block (findings.go: exact file/line + per-finding severity/confidence). When a
+// model emits no parseable block, emit falls back to a heuristic prose scrape: a
+// "path:line" reference (e.g. run/executor.go:166) anchors a finding, whose title
+// is the nearest preceding markdown heading / numbered item / bold lead-in (else
+// the first sentence of the finding's paragraph). The scrape is best-effort
+// signal for the store to aggregate, not a structured contract the reviewer
+// guarantees.
 
 import (
 	"bytes"
@@ -50,11 +53,16 @@ var pathLineRe = regexp.MustCompile(`([A-Za-z0-9_./-]+\.[A-Za-z0-9]+):(\d+)`)
 var numberedRe = regexp.MustCompile(`^\d+[.)]\s+(.+)$`)
 
 // finding is one extracted issue: where it points and a derived human title.
+// severity/confidence are populated from the structured ```gadfly-findings block
+// (extractStructuredFindings); they are empty for findings recovered by the
+// heuristic prose scrape (parseFindings), which has no per-finding signal.
 type finding struct {
 	file       string
 	line       int
 	title      string
 	detail     string
+	severity   string // per-finding: critical/high/medium/small/trivial ("" if heuristic)
+	confidence string // per-finding: high/medium/low ("" if heuristic)
 }
 
 // runPayload is the POST /runs body. Field names match the gadfly-reports API EXACTLY.
@@ -86,6 +94,7 @@ type reportPayload struct {
 	Provider    string `json:"provider"`
 	RunID       string `json:"run_id"`
 	RawSeverity string `json:"raw_severity"`
+	Confidence  string `json:"confidence"` // per-finding high/medium/low ("" if heuristic)
 	Detail      string `json:"detail"`
 }
 
@@ -129,8 +138,19 @@ func emit(results []specialistResult, elapsed time.Duration) {
 		if r.verdict == verdictClean {
 			continue
 		}
-		sev := r.verdict.label()
-		for _, f := range parseFindings(r.spec, r.out) {
+		// Prefer the model's machine-readable ```gadfly-findings block (exact
+		// location + per-finding severity). Fall back to the prose scrape when it
+		// yields NOTHING — no block, an unterminated/malformed one, or a block that
+		// parsed to zero usable findings on a non-clean lens (e.g. an empty []
+		// alongside prose findings). Falling back on empty, not just on absent,
+		// keeps the safety net from being defeated by a contradictory empty block.
+		fs := extractStructuredFindingsOrScrape(r)
+		lensSev := r.verdict.severity() // canonical word for heuristic findings (no per-finding severity)
+		for _, f := range fs {
+			sev := f.severity
+			if sev == "" {
+				sev = lensSev
+			}
 			reports = append(reports, reportPayload{
 				Repo:        repo,
 				PR:          pr,
@@ -142,6 +162,7 @@ func emit(results []specialistResult, elapsed time.Duration) {
 				Provider:    provider,
 				RunID:       runID,
 				RawSeverity: sev,
+				Confidence:  f.confidence,
 				Detail:      f.detail,
 			})
 		}

cmd/gadfly/emit_test.go

@@ -157,7 +157,7 @@ func TestEmit_PostsRunsAndReports(t *testing.T) {
 	if len(reportBody) != 2 {
 		t.Fatalf("/reports array length = %d, want 2", len(reportBody))
 	}
-	for _, k := range []string{"repo", "pr", "lens", "file", "line", "title", "model", "provider", "run_id", "raw_severity", "detail"} {
+	for _, k := range []string{"repo", "pr", "lens", "file", "line", "title", "model", "provider", "run_id", "raw_severity", "confidence", "detail"} {
 		if _, ok := reportBody[0][k]; !ok {
 			t.Errorf("/reports[0] missing field %q (got keys %v)", k, keysOf(reportBody[0]))
 		}
@@ -171,8 +171,11 @@ func TestEmit_PostsRunsAndReports(t *testing.T) {
 	if reportBody[0]["line"] != float64(166) {
 		t.Errorf("reports[0].line = %v, want 166", reportBody[0]["line"])
 	}
-	if reportBody[0]["raw_severity"] != "Blocking issues found" {
-		t.Errorf("reports[0].raw_severity = %v, want 'Blocking issues found'", reportBody[0]["raw_severity"])
+	// No structured block in sampleLensMarkdown, so this is a heuristic-scraped
+	// finding: raw_severity is the canonical word derived from the lens verdict
+	// (Blocking -> "high"), not the full verdict phrase.
+	if reportBody[0]["raw_severity"] != "high" {
+		t.Errorf("reports[0].raw_severity = %v, want 'high'", reportBody[0]["raw_severity"])
 	}
 	if reportBody[0]["run_id"] != "owner/repo#7:ollama-cloud/qwen3" {
 		t.Errorf("reports[0].run_id = %v, want owner/repo#7:ollama-cloud/qwen3", reportBody[0]["run_id"])

cmd/gadfly/findings.go

@@ -0,0 +1,236 @@
+package main
+
+// Structured findings: the machine-readable contract between a lens's output and
+// the telemetry/consolidation pipeline. Each lens is asked (see
+// scripts/system-prompt.txt) to append a fenced ```gadfly-findings code block
+// holding a JSON array of its findings. Parsing that exact block is far more
+// reliable than scraping prose with a path:line regex (emit.go's heuristic),
+// and it carries PER-FINDING severity + confidence the prose verdict can't.
+//
+// Everything here degrades gracefully: a missing, unterminated, or malformed
+// block makes extractStructuredFindings return ok=false (and yield no findings),
+// so the caller falls back to the heuristic scrape — a weak model that ignores
+// the contract still contributes findings, exactly as before.
+
+import (
+	"encoding/json"
+	"strconv"
+	"strings"
+)
+
+// structuredFinding mirrors one element of the ```gadfly-findings JSON array.
+// Line is json.Number so we tolerate both 123 and "123" from less-precise models.
+type structuredFinding struct {
+	File       string      `json:"file"`
+	Line       json.Number `json:"line"`
+	Severity   string      `json:"severity"`
+	Confidence string      `json:"confidence"`
+	Title      string      `json:"title"`
+	Detail     string      `json:"detail"` // optional; the prose paragraph is used when absent
+}
+
+// findingsFence is the info-string that tags the machine-readable block.
+const findingsFence = "gadfly-findings"
+
+// extractStructuredFindings parses the ```gadfly-findings JSON block out of a
+// lens's markdown. It returns the findings and ok=true when a TERMINATED block is
+// present AND parses as a JSON array (an empty array is valid "nothing found" —
+// ok is still true). A missing, unterminated, or unparseable block returns
+// ok=false so the caller falls back to the heuristic scrape.
+//
+// Findings are deduped by file:line (keeping the first, matching parseFindings),
+// findings with no usable file are dropped, and each title/detail is backfilled
+// from the prose when the JSON omits it (best of both: exact location + the human
+// context the model already wrote).
+func extractStructuredFindings(out string) ([]finding, bool) {
+	lines := strings.Split(out, "\n")
+	start, end, ok := findingsSpan(lines)
+	if !ok {
+		return nil, false
+	}
+	var raw []structuredFinding
+	if err := json.Unmarshal([]byte(strings.Join(lines[start+1:end], "\n")), &raw); err != nil {
+		return nil, false
+	}
+
+	findings := make([]finding, 0, len(raw))
+	seen := map[string]bool{}
+	var prose map[string]string // built lazily — only if a finding lacks its own detail
+	for _, sf := range raw {
+		file := strings.TrimSpace(sf.File)
+		if file == "" {
+			continue
+		}
+		ln := 0
+		if n, err := strconv.Atoi(strings.TrimSpace(sf.Line.String())); err == nil && n > 0 {
+			ln = n
+		}
+		key := file + ":" + strconv.Itoa(ln)
+		if ln > 0 { // only dedupe concrete locations; unknown-line findings are kept
+			if seen[key] {
+				continue
+			}
+			seen[key] = true
+		}
+		detail := strings.TrimSpace(sf.Detail)
+		if detail == "" && ln > 0 {
+			if prose == nil {
+				prose = proseParagraphs(out)
+			}
+			detail = prose[key]
+		}
+		title := strings.TrimSpace(sf.Title)
+		if title == "" { // never empty: fall back to the prose detail, then the location
+			if detail != "" {
+				title = truncate(detail, 120)
+			} else if ln > 0 {
+				title = key
+			} else {
+				title = file
+			}
+		}
+		findings = append(findings, finding{
+			file:       file,
+			line:       ln,
+			title:      title,
+			detail:     truncate(detail, 500),
+			severity:   normalizeSeverity(sf.Severity),
+			confidence: normalizeConfidence(sf.Confidence),
+		})
+		if len(findings) >= maxFindingsPerLens {
+			break
+		}
+	}
+	return findings, true
+}
+
+// extractStructuredFindingsOrScrape returns a lens's findings, preferring the
+// structured ```gadfly-findings block and falling back to the heuristic prose
+// scrape when the block is absent, unterminated/malformed, OR parsed to zero
+// usable findings (e.g. an empty [] emitted alongside real prose findings).
+// Factored out of emit() so the fallback rule is unit-testable.
+func extractStructuredFindingsOrScrape(r specialistResult) []finding {
+	if fs, _ := extractStructuredFindings(r.out); len(fs) > 0 {
+		return fs
+	}
+	return parseFindings(r.spec, r.out)
+}
+
+// stripFindingsBlock removes every TERMINATED ```gadfly-findings block from out so
+// the machine-readable JSON never shows in the rendered comment. An UNTERMINATED
+// fence is left in place — treating it as a block would swallow the rest of the
+// comment (e.g. when a model's output was truncated mid-block). Trailing
+// whitespace is trimmed.
+func stripFindingsBlock(out string) string {
+	lines := strings.Split(out, "\n")
+	for {
+		start, end, ok := findingsSpan(lines)
+		if !ok {
+			break
+		}
+		lines = append(lines[:start:start], lines[end+1:]...)
+	}
+	return strings.TrimRight(strings.Join(lines, "\n"), "\n")
+}
+
+// findingsSpan returns the [start,end] inclusive line indices of the first
+// TERMINATED ```gadfly-findings block in lines (start = the opening fence, end =
+// the closing fence), or ok=false when there is none or it is unterminated.
+// extract and strip share it so they always agree on what is (and isn't) a block.
+func findingsSpan(lines []string) (start, end int, ok bool) {
+	start = -1
+	for i, ln := range lines {
+		if isFindingsOpen(ln) {
+			start = i
+			break
+		}
+	}
+	if start < 0 {
+		return 0, 0, false
+	}
+	for j := start + 1; j < len(lines); j++ {
+		if isFenceClose(lines[j]) {
+			return start, j, true
+		}
+	}
+	return 0, 0, false // unterminated
+}
+
+// fenceInfo returns the info-string (text after the backticks) of a code-fence
+// line and whether the line opens/closes a fence at all. A bare ``` yields ("",
+// true); ```gadfly-findings yields ("gadfly-findings", true).
+func fenceInfo(line string) (string, bool) {
+	t := strings.TrimSpace(line)
+	if !strings.HasPrefix(t, "```") {
+		return "", false
+	}
+	return strings.TrimSpace(strings.TrimLeft(t, "`")), true
+}
+
+// isFindingsOpen reports whether line opens a ```gadfly-findings block, matching
+// the info-string EXACTLY (not as a substring) so a fence like ```not-findings
+// can't masquerade as ours.
+func isFindingsOpen(line string) bool {
+	info, ok := fenceInfo(line)
+	return ok && info == findingsFence
+}
+
+// isFenceClose reports whether line is a bare closing fence (``` with no info).
+func isFenceClose(line string) bool {
+	info, ok := fenceInfo(line)
+	return ok && info == ""
+}
+
+// proseParagraphs maps "file:line" -> the prose paragraph that first references
+// it, so a structured finding without its own detail can borrow the human
+// context the model already wrote. Built from the markdown OUTSIDE the findings
+// block (the block is JSON, not prose).
+func proseParagraphs(out string) map[string]string {
+	prose := stripFindingsBlock(out)
+	lines := strings.Split(prose, "\n")
+	m := map[string]string{}
+	for _, loc := range pathLineRe.FindAllStringSubmatchIndex(prose, -1) {
+		key := prose[loc[2]:loc[3]] + ":" + prose[loc[4]:loc[5]]
+		if _, dup := m[key]; dup {
+			continue
+		}
+		li := strings.Count(prose[:loc[0]], "\n")
+		m[key] = paragraphAt(lines, li)
+	}
+	return m
+}
+
+// normalizeSeverity maps a model's severity word onto the canonical set
+// (critical/high/medium/small/trivial), accepting common synonyms. An
+// unrecognized value is returned lowercased so the store still sees the raw word.
+func normalizeSeverity(s string) string {
+	switch t := strings.ToLower(strings.TrimSpace(s)); t {
+	case "critical", "crit", "blocker", "blocking":
+		return "critical"
+	case "high", "major", "severe":
+		return "high"
+	case "medium", "moderate":
+		return "medium"
+	case "small", "low", "minor":
+		return "small"
+	case "trivial", "nit", "nitpick", "info", "informational", "style", "cosmetic":
+		return "trivial"
+	default:
+		return t
+	}
+}
+
+// normalizeConfidence maps a model's confidence word onto high/medium/low,
+// accepting common synonyms; an unrecognized value is returned lowercased.
+func normalizeConfidence(s string) string {
+	switch t := strings.ToLower(strings.TrimSpace(s)); t {
+	case "high", "certain", "confirmed", "verified":
+		return "high"
+	case "medium", "med", "moderate":
+		return "medium"
+	case "low", "unsure", "tentative", "unverified", "speculative":
+		return "low"
+	default:
+		return t
+	}
+}

cmd/gadfly/findings_test.go

@@ -0,0 +1,146 @@
+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+const sampleReview = "**Blocking issues found**\n\n" +
+	"- **Unauthenticated endpoint** — `model.go:184` leaks PR content to a third party.\n" +
+	"- A nit about naming in `util.go:12`.\n\n" +
+	"```gadfly-findings\n" +
+	"[\n" +
+	"  {\"file\": \"model.go\", \"line\": 184, \"severity\": \"high\", \"confidence\": \"high\", \"title\": \"Unauthenticated endpoint\"},\n" +
+	"  {\"file\": \"util.go\", \"line\": 12, \"severity\": \"nit\", \"confidence\": \"medium\", \"title\": \"naming\"}\n" +
+	"]\n" +
+	"```\n"
+
+func TestExtractStructuredFindings(t *testing.T) {
+	fs, ok := extractStructuredFindings(sampleReview)
+	if !ok {
+		t.Fatal("expected ok=true for a well-formed block")
+	}
+	if len(fs) != 2 {
+		t.Fatalf("want 2 findings, got %d", len(fs))
+	}
+	if fs[0].file != "model.go" || fs[0].line != 184 || fs[0].severity != "high" || fs[0].confidence != "high" {
+		t.Errorf("finding[0] mismatch: %+v", fs[0])
+	}
+	// "nit" must normalize to the canonical "trivial".
+	if fs[1].severity != "trivial" {
+		t.Errorf("want severity normalized to trivial, got %q", fs[1].severity)
+	}
+	// Detail is borrowed from the prose paragraph referencing the same file:line.
+	if fs[0].detail == "" {
+		t.Error("expected detail borrowed from prose, got empty")
+	}
+}
+
+func TestExtractStructuredFindingsEmptyArray(t *testing.T) {
+	out := "No material issues found\n\n```gadfly-findings\n[]\n```\n"
+	fs, ok := extractStructuredFindings(out)
+	if !ok {
+		t.Fatal("an empty array is a valid block; want ok=true")
+	}
+	if len(fs) != 0 {
+		t.Fatalf("want 0 findings, got %d", len(fs))
+	}
+}
+
+func TestExtractStructuredFindingsFallback(t *testing.T) {
+	// No block at all -> ok=false so the caller uses the heuristic scrape.
+	if _, ok := extractStructuredFindings("Minor issues\n\n- something at `x.go:1`\n"); ok {
+		t.Error("want ok=false when there is no block")
+	}
+	// Malformed JSON -> ok=false (graceful fallback).
+	bad := "Minor issues\n\n```gadfly-findings\n{not json}\n```\n"
+	if _, ok := extractStructuredFindings(bad); ok {
+		t.Error("want ok=false for malformed JSON")
+	}
+}
+
+func TestExtractStructuredFindingsStringLine(t *testing.T) {
+	// Tolerate a quoted line number from a less-precise model.
+	out := "Minor issues\n\n```gadfly-findings\n[{\"file\":\"a.go\",\"line\":\"42\",\"severity\":\"medium\",\"title\":\"x\"}]\n```\n"
+	fs, ok := extractStructuredFindings(out)
+	if !ok || len(fs) != 1 || fs[0].line != 42 {
+		t.Fatalf("want one finding at line 42, got ok=%v %+v", ok, fs)
+	}
+}
+
+func TestStripFindingsBlock(t *testing.T) {
+	stripped := stripFindingsBlock(sampleReview)
+	if strings.Contains(stripped, findingsFence) {
+		t.Errorf("block not stripped: %q", stripped)
+	}
+	// The prose findings must survive.
+	if !strings.Contains(stripped, "Unauthenticated endpoint") || !strings.Contains(stripped, "util.go:12") {
+		t.Errorf("prose lost during strip: %q", stripped)
+	}
+}
+
+func TestStripFindingsBlockUnterminated(t *testing.T) {
+	// A truncated, unterminated block must NOT swallow the prose before it.
+	out := "Minor issues\n\n- real finding at `x.go:1`\n\n```gadfly-findings\n[{\"file\":\"x.go\""
+	got := stripFindingsBlock(out)
+	if !strings.Contains(got, "real finding at `x.go:1`") {
+		t.Errorf("unterminated block swallowed the prose: %q", got)
+	}
+}
+
+func TestStripFindingsBlockNoBlock(t *testing.T) {
+	in := "Minor issues\n\n- finding at `x.go:9`"
+	if out := stripFindingsBlock(in); out != in {
+		t.Errorf("strip changed block-free text: %q != %q", out, in)
+	}
+}
+
+func TestNormalizeSeverity(t *testing.T) {
+	cases := map[string]string{
+		"Critical": "critical", "blocker": "critical",
+		"major": "high", "HIGH": "high",
+		"moderate": "medium",
+		"minor":    "small", "low": "small", // "minor" and "low" both map to small (consistently)
+		"nit": "trivial", "Style": "trivial",
+		"weird": "weird", // unknown passes through, lowercased
+	}
+	for in, want := range cases {
+		if got := normalizeSeverity(in); got != want {
+			t.Errorf("normalizeSeverity(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
+
+func TestNormalizeConfidence(t *testing.T) {
+	cases := map[string]string{
+		"High": "high", "confirmed": "high",
+		"MEDIUM": "medium", "moderate": "medium",
+		"low": "low", "unverified": "low",
+		"hunch": "hunch", // unknown passes through, lowercased
+	}
+	for in, want := range cases {
+		if got := normalizeConfidence(in); got != want {
+			t.Errorf("normalizeConfidence(%q) = %q, want %q", in, got, want)
+		}
+	}
+}
+
+func TestExtractStructuredFindingsFallbackOnEmpty(t *testing.T) {
+	// A non-clean lens that emitted an empty [] but listed prose findings must
+	// fall through to the heuristic scrape, not silently drop everything.
+	out := "Minor issues\n\n- bug at `pkg/a.go:7`\n\n```gadfly-findings\n[]\n```\n"
+	r := specialistResult{spec: Specialist{Name: "correctness"}, out: out, verdict: verdictMinor}
+	fs := extractStructuredFindingsOrScrape(r)
+	if len(fs) == 0 {
+		t.Fatal("empty [] must fall back to the heuristic scrape, got no findings")
+	}
+	if fs[0].file != "pkg/a.go" || fs[0].line != 7 {
+		t.Errorf("heuristic fallback wrong: %+v", fs[0])
+	}
+}
+
+func TestVerdictSeverity(t *testing.T) {
+	if verdictBlocking.severity() != "high" || verdictMinor.severity() != "small" || verdictUnknown.severity() != "trivial" {
+		t.Error("verdict.severity mapping changed unexpectedly")
+	}
+}

cmd/gadfly/recheck.go

@@ -49,6 +49,11 @@ Output rules:
 - Do NOT invent new findings; this is a verification gate, not a fresh review.
 - Do NOT include meta-commentary about the verification process or which
   findings you dropped — output only the final, corrected review markdown.
+- The draft ends with a fenced ` + "`gadfly-findings`" + ` JSON block. Regenerate it
+  so it lists ONLY the findings that SURVIVED your verification, in the same schema
+  ({"file","line","severity","confidence","title"}; severity one of
+  critical/high/medium/small/trivial, confidence one of high/medium/low). If every
+  finding was dropped, emit an empty array ` + "`[]`" + `. Keep the block last.
 - When done investigating, STOP calling tools and reply with the review.`
 
 // recheckEnabled reports whether the verification pass should run. On unless

scripts/system-prompt.txt

@@ -43,3 +43,21 @@ Output rules:
 - Only report issues you are reasonably confident are real after checking. If the diff
   is clean, say so plainly rather than inventing nits.
 - When you are done investigating, STOP calling tools and reply with the final review.
+
+Machine-readable findings — AFTER the prose review, append ONE fenced code block,
+tagged `gadfly-findings`, holding a JSON array of the SAME findings you described above
+(this block is consumed by tooling and hidden from the rendered comment):
+
+```gadfly-findings
+[
+  {"file": "path/to/file.go", "line": 123, "severity": "high", "confidence": "high", "title": "one-line summary of the issue"}
+]
+```
+
+- One object per real finding, in the same order as your prose. `file`/`line` must be a
+  concrete location you verified (the line the issue is at). `severity` is one of
+  `critical`, `high`, `medium`, `small`, `trivial`. `confidence` is your post-verification
+  confidence the issue is real: one of `high`, `medium`, `low`.
+- Include ONLY genuine problems — never verification notes ("confirmed X is safe at f:line"),
+  and never an "Outside my lens:" aside. If your lens is clean, emit an empty array `[]`.
+- This block is in ADDITION to the prose; do not drop the human-readable findings.