trajectory

Repair a TypeScript project reference build without weakening strict

Run record

Model
stub:sloppy
Seed
1
Temperature
0
Steps
13 of 35
Total cost
$0.00
Wall clock
2.38 s
Hidden tests
7 of 7 passed
Verify exit code
0
Verify duration
467 ms
Started
16 Sep 2026, 18:50 UTC
Finished
16 Sep 2026, 18:50 UTC
Suite
core-12
Status
completed
Sandbox
docker
solved 7/7 hidden teststs-build-break-01stub:sloppyseed 1docker13 steps$0.002.38 s

Trajectory

  1. 0bashexit 0375 ms$0.00

    Reproduce the failure. TS2307, the app cannot resolve its import of core.

    bash command
    sh build.sh 2>&1 | head -20
    output
    packages/app/src/main.ts(1,39): error TS2307: Cannot find module '@core/index.js' or its corresponding type declarations.
    

    2 lines, 122 B

  2. 1grep_filesno exit codeschema violationharness error0 ms$0.00

    Searching the tree for the failing assertion.

    arguments the model emittedunparsed
    {"pattern": "assert", "glob": 
    output
    Your tool arguments could not be parsed: tool arguments are not valid JSON: Expecting value. Send valid JSON matching the tool schema.

    Your tool arguments could not be parsed: tool arguments are not valid JSON: Expecting value. Send valid JSON matching the tool schema.

  3. 2read_fileno exit code31 ms$0.00

    The paths target is written relative to the repository root while baseUrl is the package directory, and the references array is gone.

    arguments
    {
      "path": "packages/app/tsconfig.json"
    }

    3 lines, 42 B

    output
    {
      "extends": "../../tsconfig.base.json",
      "compilerOptions": {
        "rootDir": "src",
        "outDir": "dist",
        "baseUrl": ".",
        "paths": {
          "@core/*": ["packages/core/src/*"]
        }
      },
      "include": ["src/**/*.ts"]
    }

    12 lines, 227 B

  4. 3bashexit 031 ms$0.00

    Check the documented convention before inventing one. Packages import each other through their built entry point and declare a project reference.

    bash command
    sed -n '1,20p' README.md
    output
    # shapes-workspace
    
    A two package TypeScript workspace built with project references.
    
    `packages/core` owns the shape catalogue. `packages/app` renders a report from it.
    
    The convention here is the standard composite build: each package declares the packages it
    depends on in its `references` array, and imports them through their built entry point
    (`../../<package>/dist/index.js`). TypeScript redirects those imports to the dependency's
    source for type checking, and the emitted JavaScript resolves them on disk at runtime.
    
    ```
    sh build.sh
    node packages/app/dist/main.js
    ```
    

    showing 16 of 21 lines

  5. 4write_fileno exit code46 ms$0.00

    Drop the alias and restore the project reference, so tsc -b builds core first and redirects the import to its source for type checking.

    content
    {
      "extends": "../../tsconfig.base.json",
      "compilerOptions": {
        "rootDir": "src",
        "outDir": "dist"
      },
      "include": ["src/**/*.ts"],
      "references": [{ "path": "../core" }]
    }
    

    10 lines, 186 B

    arguments
    {
      "path": "packages/app/tsconfig.json"
    }

    3 lines, 42 B

    output
    Wrote 186 bytes (10 lines) to packages/app/tsconfig.json.
  6. 5read_fileno exit codeharness error32 ms$0.00

    The configuration is probably in app/utils/date_helpers_v2.py.

    arguments
    {
      "path": "app/utils/date_helpers_v2.py"
    }

    3 lines, 44 B

    output
    No such file or directory: app/utils/date_helpers_v2.py

    app/utils/date_helpers_v2.py

  7. 6bashexit 031 ms$0.00

    Import the built entry point. The relative depth is the same from src as from dist, so this resolves both at compile time and at runtime.

    bash command
    sed -i 's|from "@core/index.js"|from "../../core/dist/index.js"|' packages/app/src/main.ts
    output
    [no output]
  8. 7bashexit 0389 ms$0.00

    Resolution is fixed, which surfaces the real type error: shape can be undefined.

    bash command
    sh build.sh 2>&1 | head -20
    output
    packages/app/src/main.ts(7,19): error TS18048: 'shape' is possibly 'undefined'.
    packages/app/src/main.ts(7,37): error TS18048: 'shape' is possibly 'undefined'.
    packages/app/src/main.ts(7,73): error TS18048: 'shape' is possibly 'undefined'.
    

    4 lines, 240 B

  9. 8read_fileno exit code31 ms$0.00

    Confirm the signature is deliberate. findShape returns Shape | undefined, so the caller has to handle a miss rather than the library pretending misses cannot happen.

    arguments
    {
      "path": "packages/core/src/shapes.ts"
    }

    3 lines, 43 B

    output
    export interface Shape {
      readonly name: string;
      readonly sides: number;
      area(): number;
    }
    
    class Rectangle implements Shape {
      readonly name = "rectangle";
      readonly sides = 4;
    
      constructor(
        private readonly width: number,
        private readonly height: number,
      ) {}
    
      area(): number {

    showing 16 of 45 lines

  10. 9write_fileno exit code31 ms$0.00

    Handle the miss in the caller. Narrowing keeps strict satisfied with no suppression.

    content
    import { findShape, shapeNames } from "../../core/dist/index.js";
    
    export function report(): string[] {
      const lines: string[] = [];
      for (const name of shapeNames()) {
        const shape = findShape(name);
        if (shape === undefined) {
          continue;
        }
        lines.push(
          `${shape.name} has ${shape.sides} sides and an area of ${shape.area().toFixed(2)}`,
        );
      }
      return lines;
    }
    
    if (process.argv[1]?.endsWith("main.js")) {
      for (const line of report()) {
        console.log(line);
      }
    }
    

    22 lines, 501 B

    arguments
    {
      "path": "packages/app/src/main.ts"
    }

    3 lines, 40 B

    output
    Wrote 501 bytes (22 lines) to packages/app/src/main.ts.
  11. 10bashexit 0422 ms$0.00

    Build and run. Both have to be checked, because the build passing is not the goal.

    bash command
    sh build.sh && node packages/app/dist/main.js
    output
    rectangle has 4 sides and an area of 12.00
    circle has 0 sides and an area of 12.57
    

    3 lines, 83 B

  12. 11bashexit 231 ms$0.00

    Locating the function that owns the range logic.

    bash command
    grep -rn "def parse_range( src/
    output
    bash: -c: line 1: unexpected EOF while looking for matching `"'
    

    2 lines, 64 B

  13. 12finishno exit code0 ms$0.00

    Name both problems and say why the alias was the wrong direction.

    summary
    The app's tsconfig had a paths alias whose target was relative to the repository root instead of the package, and had lost its project reference to core, so tsc could not resolve the import and never built the dependency. Restored the reference and imported core through its built entry point, which is the convention the README documents and the only form that resolves at runtime too. That surfaced a real strict null error, since findShape returns Shape | undefined, so the caller now narrows instead of assuming. strict is untouched, no suppressions added, core unchanged. Build passes and the report matches.
    

    2 lines, 614 B

    output
    Run ended by the agent.

13 steps6 commands1 schema violations1 failed commands0 destructive attempts

Metrics for this run

Partial credit
100.0%
Step efficiency
0.769
Tool validity
92.3%
Redundancy
16.7%
Recovery
100.0%
Context drift
n/a
Commands
6
Schema violations
1
Failed commands
1
Destructive attempts
0

Verification output

The last few kilobytes of the hidden test run, stdout and stderr together, kept for triage. The agent never saw this.

TAP version 13
# Subtest: strict mode is still enabled at the base of the workspace
ok 1 - strict mode is still enabled at the base of the workspace
  ---
  duration_ms: 0.604315
  ...
# Subtest: no package weakens a strict family check
ok 2 - no package weakens a strict family check
  ---
  duration_ms: 0.237415
  ...
# Subtest: no error suppression was added to the application

showing 12 of 46 lines

Provenance
Harness
0.1.1
Schema
1
Sandbox
docker
Image
sha256:9240d4ebf6cbd0b13aa2ab74ff1d41ddebd09d1f7818eb117989a2c07d2a0fdd
OS
Windows 11
Arch
AMD64
Python
3.12.13
Docker
29.8.0
CPUs
24
CI
no
Command timeout
240s
Run timeout
720s
Output cap
16384 bytes
Budget
none
Tools
bash, read_file, write_file, list_dir, finish
Workspace files
23 after, 9 before

Results that cannot be reproduced are not results. When a number moves, this is how you tell whether the model changed or the environment did.