- New --doc-map flag (DOC_MAP_FILE env var): path to YAML config mapping
  source path globs to governing design docs
- New --doc-map-max-bytes flag (DOC_MAP_MAX_BYTES env var): cap on total
  injected doc content, default 100KB
- review/docmap.go: DocMapConfig parsing, glob matching with ** support,
  doc loading via VCS with directory expansion and size guard
- budget.Sections: new DesignDocs field, trimmed after conventions
- budget.buildResult: injects DesignDocs under ## Design Documents heading
- action.yml: doc-map and doc-map-max-bytes inputs wired to env vars
- CHANGELOG.md: created with unreleased entry
- Tests: ParseDocMapConfig, MatchDocs, globMatch, LoadMatchingDocs

@@ -0,0 +1,194 @@
+# Plan: Issue #137 — doc-map input for path-scoped doc injection

@@ -0,0 +54,4 @@
+		return nil, fmt.Errorf("read doc-map file %q: %w", localPath, err)
+	}
+
+	var cfg DocMapConfig

@@ -0,0 +198,4 @@
+			continue
+		}
+
+		for _, entry := range entries {

@@ -0,0 +242,4 @@
+	content string
+}
+
+// loadDocEntries returns the doc content for a given path.

@@ -0,0 +11,4 @@
+
+// fakeDocFetcher is a mock DocFetcher for tests.
+type fakeDocFetcher struct {
+	files map[string]string // path -> content

@@ -0,0 +335,4 @@
+	}
+}
+
+func TestLoadMatchingDocs_ContextSizeGuard(t *testing.T) {

@@ -185,6 +187,10 @@ func buildResult(s Sections, trimmed []string, estTokens int) Result {
 		sys.WriteString("\n\n## Repository Conventions\n\nThe repository has the following coding conventions that must be respected:\n\n")

@@ -0,0 +165,4 @@
+// a formatted string suitable for injection into the system prompt.
+//
+// Behavior:
+//   - Paths that look like directories (end with /, or GetAllFilesInPath returns files)

@@ -0,0 +226,4 @@
+				sb.WriteString("\n> ⚠️ (truncated — size limit reached)\n")
+			}
+			totalBytes += len(content)
+			slog.Debug("doc-map: injected doc", "path", entry.path, "bytes", len(content))

@@ -0,0 +1,303 @@
+// Package review provides doc-map parsing and doc injection for path-scoped

@@ -0,0 +50,4 @@
+// Unknown top-level keys produce a warning but are not fatal.
+func ParseDocMapConfig(localPath string) (*DocMapConfig, error) {
+	data, err := readFileBytes(localPath)
+	if err != nil {

@@ -0,0 +229,4 @@
+			slog.Debug("doc-map: injected doc", "path", entry.path, "bytes", len(content))
+		}
+	}
+

@@ -0,0 +1,194 @@
+# Plan: Issue #137 — doc-map input for path-scoped doc injection

@@ -0,0 +1,332 @@
+// doc-map parsing and doc injection for path-scoped design document context in AI code reviews.

@@ -0,0 +54,4 @@
+	}
+
+	var cfg DocMapConfig
+	if err := yaml.UnmarshalWithOptions(data, &cfg, yaml.Strict()); err != nil {

@@ -0,0 +167,4 @@
+//   - Paths that look like directories (end with /, or GetAllFilesInPath returns files)
+//     are expanded to all .md files under them.
+//   - Missing files are logged as warnings and skipped.
+//   - Total content is capped at opts.MaxBytes; truncation is noted inline.

@@ -0,0 +299,4 @@
+}
+
+// validateDocPath rejects doc paths that could cause path traversal via the
+// VCS API (absolute paths, any ".." segment). Defense-in-depth: the VCS API

@@ -0,0 +11,4 @@
+
+// fakeDocFetcher is a mock DocFetcher for tests.
+type fakeDocFetcher struct {
+	files map[string]string // path -> content

@@ -0,0 +232,4 @@
+	if sb.Len() == 0 {
+		return "", nil
+	}
+	return sb.String(), nil

@@ -0,0 +293,4 @@
+	}
+}
+
+// readFileBytes reads the contents of a local file.

@@ -353,0 +372,4 @@
+			changedPaths = append(changedPaths, f.Filename)
+		}
+
+		matchedDocs := review.MatchDocs(docMapCfg, changedPaths)

@@ -0,0 +155,4 @@
+		}
+		patParts = patParts[1:]
+		pathParts = pathParts[1:]
+	}

@@ -0,0 +19,4 @@
+)
+
+// DocMapping maps a set of path glob patterns to governing doc files/directories.
+type DocMapping struct {

@@ -0,0 +86,4 @@
+					result = append(result, doc)
+				}
+			}
+		}

@@ -0,0 +159,4 @@
+	// All pattern parts consumed; path must also be consumed.
+	return len(pathParts) == 0
+}
+

@@ -0,0 +196,4 @@
+			slog.Debug("doc-map: no .md files found under path", "path", docPath)
+			continue
+		}
+

@@ -0,0 +250,4 @@
+	}
+
+	// Try directory expansion first.
+	files, dirErr := fetcher.GetAllFilesInPath(ctx, owner, repo, docPath)

@@ -0,0 +7,4 @@
+	"path/filepath"
+	"strings"
+	"testing"
+)

@@ -350,6 +352,46 @@ func main() {
 		slog.Debug("loaded system prompt file", "file", *systemPromptFile, "bytes", len(additionalPrompt))