Debug Outfitter

Systematic debugging process for @outfitter/* package issues.

Goal

Investigate issues methodically and produce a structured report documenting:

1. What was observed (symptoms)
2. What was investigated (evidence)
3. What was found (root cause)
4. What to do about it (fix or escalation)

Constraints

DO:

• Gather evidence before forming hypotheses
• Use the diagnostic patterns in this skill
• Reference outfitter-atlas for correct patterns
• Assign a confidence level to your diagnosis
• Produce a Debug Report at the end

DON'T:

• Apply random fixes hoping something works
• Skip the evidence collection phase
• Leave issues undiagnosed
• Forget to document findings

Steps

1. Load the outfitter-atlas skill to gain expertise in the Outfitter packages.
2. Collect evidence — gather symptoms before hypothesizing
3. Categorize the issue — identify which area is affected
4. Investigate — use category-specific diagnostics
5. Produce a Debug Report using TEMPLATE.md
6. If the issue is in Outfitter's packages themselves, escalate via outfitter-issue

Stage 1: Evidence Collection

Gather symptoms before forming hypotheses.

What to Collect

• Error messages and stack traces
• Unexpected output vs expected output
• Exit codes (actual vs expected)
• Relevant code snippets
• Environment details (Bun version, package versions)

Quick Diagnostic Commands

# Check package versions
bun pm ls | grep @outfitter

# Find Result usage patterns
rg "Result\.(ok|err)" --type ts -A 2

# Find error handling
rg "isErr\(\)|isOk\(\)" --type ts -A 3

# Check for thrown exceptions (anti-pattern)
rg "throw new" --type ts

Stage 2: Categorize the Issue

Based on symptoms, identify the issue category:

Category	Symptoms	Common Causes
Result Handling	Wrong value, type errors	Missing await, reassignment breaking narrowing
MCP Issues	Tool not appearing, invocation failing	Registration order, missing schema descriptions
CLI Output	Wrong format, missing data	Mode detection, await on output
Exit Codes	Wrong exit code	Not using exitWithError, manual process.exit
Logging	Missing logs, sensitive data exposed	Wrong level, redaction disabled
Validation	Unexpected validation errors	Schema mismatch, missing .describe()

Stage 3: Targeted Investigation

Result Handling Issues

Always getting error:

// Check: Missing await?
const result = getUser(id); // ❌ Promise, not Result!
const result = await getUser(id); // ✅

// Check: Validation failing?
const validated = validate(input);
if (validated.isErr()) {
  console.log("Validation failed:", validated.error.context);
}

Type narrowing broken:

// ❌ Reassigning breaks narrowing
let result = await getUser(id);
if (result.isOk()) {
  result = await updateUser(result.value); // Breaks!
}

// ✅ Separate variables
const getResult = await getUser(id);
if (getResult.isErr()) return getResult;
const updateResult = await updateUser(getResult.value);

Error type lost:

// Use _tag for narrowing
if (result.isErr()) {
  switch (result.error._tag) {
    case "ValidationError":
      console.log(result.error.context);
      break;
    case "NotFoundError":
      console.log(result.error.resourceId);
      break;
  }
}

MCP Issues

Tool not appearing:

1. Verify registration happens before start():

   server.registerTool(myTool);
   server.start(); // After registration!
   

2. Check schema has .describe() on all fields:

   const schema = z.object({
     query: z.string().describe("Required for AI"),
   });
   

Tool invocation failing:

1. Handler must be async:

   handler: async (input) => {
     // Not sync!
     return Result.ok(data);
   };
   

2. Must return Result:

   // ❌ return { data: "value" };
   // ✅ return Result.ok({ data: "value" });
   

CLI Output Issues

JSON not printing:

// Force mode
await output(data, { mode: "json" });

// Check environment
// OUTFITTER_JSON=1 forces JSON
// OUTFITTER_JSON=0 forces human when no explicit mode is set

// Await output before exit
await output(data); // ✅
// process.exit(0);  // May exit before output completes

Wrong exit code:

// ❌ process.exit(1);
// ✅ exitWithError(result.error);

Exit code reference:

Category	Exit
validation	1
not_found	2
conflict	3
permission	4
timeout	5
rate_limit	6
network	7
internal	8
auth	9
cancelled	130

Logging Issues

Redaction not working:

const logger = createLogger({
  redaction: { enabled: true }, // Must be true!
  // Custom patterns
  redaction: {
    enabled: true,
    patterns: ["password", "apiKey", "myCustomSecret"],
  },
});

Missing context:

const requestLogger = createChildLogger(ctx.logger, {
  requestId: ctx.requestId,
  handler: "myHandler",
});
requestLogger.info("Processing", { data }); // Includes requestId

Wrong level:

// Hierarchy: trace < debug < info < warn < error < fatal
// "info" hides trace and debug
const logger = createLogger({
  level: process.env.LOG_LEVEL || "info",
});

Stage 4: Document Findings

Assess confidence in your diagnosis:

Confidence	Meaning
High	Clear pattern violation or bug found with evidence
Medium	Likely cause identified, may need verification
Low	Multiple possibilities remain, needs more investigation

Based on diagnosis, recommend:

• Code fix — Provide specific fix with before/after
• Pattern guidance — Reference correct pattern from fieldguide
• Escalation — If issue is in Outfitter itself, use outfitter-issue

Produce a Debug Report using TEMPLATE.md.

When to Escalate

If investigation reveals an issue in @outfitter/* packages themselves (not user code):

1. Document the issue clearly in the Debug Report
2. Recommend using outfitter-issue skill to file an issue
3. Include reproduction steps and expected vs actual behavior

Related Skills

• outfitter-atlas — Correct patterns reference
• outfitter-check — Compliance verification
• outfitter-issue — Report issues to Outfitter team