Callidescope Trace

Running callidescope and reading what it says

Callidescope builds one call graph for a TypeScript workspace and measures the shape of it. It follows calls through injected dependencies — the hop from this.someService.load() into SomeService.load — which is the edge no file-at-a-time tool can see, and where most of a framework codebase's control flow actually lives.

Three commands, answering three different questions:

npx callidescope                                        # the whole workspace
npx callidescope depth --addresses src/foo.service.ts#FooService.bar    # one callable, vertically
npx callidescope breadth --addresses src/foo.service.ts#FooService.bar  # one callable, horizontally

A repository with no configuration file is traced with defaults rather than told to write one, so a bare run always produces something. What a run gates on and what it writes are both opt-in and both live in the callidescope-configure skill; this one is about reading the result.

callidescope: the whole workspace

Reports four findings.

Deep call stacks. The single deepest path below each entry point, when it exceeds limits.maximumDepth. Only one path per entry point is ever built, so a wide graph costs no more than a narrow one.

Module spread. A callable whose transitive callees reach many unrelated modules and which calls several of them directly. Both conditions matter: transitive reach alone flags every entry point, because an entry point legitimately reaches the whole program. A spread row is therefore specifically a callable personally orchestrating unrelated concerns.

Breadth. How many callables one callable calls directly. Reported always; gated only when limits.maximumBreadth is set, which is the one limit with no default.

Possibly misplaced callables. A callable whose callers nearly all sit in one other module of the same project. The output is a concrete move.

Reading a stack

Stack #1 | 🚨 [DEPTH ≥ 10 > 6] (decorated-method)
🚀 SomeCommand.run(options: SomeOptions): Promise<void> [.../some.command.ts:220]
   ↳ Measure the repository and write every configured output.
  └─> SomeService.measure(args: MeasureArguments): Result [.../some.service.ts:115]
     ↳ Measure aggregated statistics for the provided directory.

• ≥ 10 is a floor, not a measurement. Something on that path could not be followed — a callback invoked through a parameter, a computed member name — and the run says so rather than quietly under-reporting. The real depth is at least ten. Not a defect, and not a number to distrust: ≥ 10 against a limit of 6 is a genuine failure. Unfollowable calls in the summary counts them.
• The parenthesized kind is the entry-point rule that claimed the root. orphan-root means nothing in the repository calls it: either dead code, or an entry-point rule the configuration is missing.
• Every frame carries file:line, so the next step is opening one.
• Each frame is annotated from the type checker — the signature, and the JSDoc prose collapsed to one line — which is what makes a stack readable rather than a list of places to go look. A frame printed (…): ReturnType had a signature over 80 characters, almost always a constructor taking a dozen injected services. A summary over 120 characters prints only its opening sentence, unmarked; only a single sentence with no boundary to cut on is trimmed and marked ….

Shortening applies to the printed tree only. The JSON report carries every comment in full, so a script wanting complete text should read JSON rather than parse the tree.

The mermaid rendering draws all the stacks as one flowchart, not one apiece. A single stack is a straight line, and a straight line is a list with extra steps; drawn together the shared tails converge — every command reaching the same repository, every resolver ending in the same service — and that convergence is what a picture shows and an indented tree cannot. Entry points are stadiums and everything else boxes, shape rather than color because the diagram is read in whichever theme the reader has. A diagram stops at 300 callables, drops whole stacks rather than trimming so it never contains an edge into something it did not draw, and says how many it left out.

Addressing one callable

depth and breadth take <file>#<qualified-name> — the file path and the qualified name callidescope already prints in every stack frame, joined by #. It is the same shape a Python traceback or an ESLint rule id uses, which means it is exactly what you can copy out of a report.

A file holding more than one declaration under the same qualified name — two overloads, two callbacks bound to the same property — is disambiguated with a trailing :<line>:

npx callidescope depth --addresses src/foo.service.ts#FooService.bar:118

When it cannot tell which one was meant, the run says so and prints every candidate's line, so the disambiguated address is a copy away.

Neither command writes anything, compares a destination, or takes --check, --write, --json, or --markdown. A lookup only ever prints. Both do take the same workspace-scoping flags as callidescope itself, because resolving an address still means tracing the workspace first.

breadth: what it calls, and what calls it

Prints the callable's direct callees and direct callers side by side — the two questions a refactor or a rename needs answered together, before either one is safe.

• A rename. The callers are the exhaustive list of what has to be updated. This is the one question a text search answers badly in a dependency-injected codebase: a call through this.someService.load() is found by the type checker and missed by a grep for the class name.
• An extraction. Extracting a responsibility out of a wide callable means moving some subset of the callees it names. The callee list is the raw material for choosing the seam — look for the subset that shares a concern, and take those.
• An inline. A callable with one caller and few callees is a candidate for folding into that caller. Breadth confirms the "one caller" part rather than assuming it.

It reports on a callable nobody has flagged. It does not need a finding to be worth running.

depth: every chain above and below

Prints every path above the callable and every path below it — every caller chain up to a root, every callee chain down to a leaf — rather than folding each direction into the single deepest one that callidescope's own report keeps.

That difference is the point. The workspace report answers "how deep does this get", so one path per entry point is enough. depth answers "what is this callable actually part of", and a callable reached from a dozen places, or reaching a dozen leaves, is exactly the shape it is asked to show in full.

Each direction is capped at 200 paths, and a capped run says so. The cap exists because a widely-called utility whose callees fan out just as wide multiplies those branches together — enumerating every path is not bounded by construction the way one deepest path is.

• Turning a depth finding into a plan. The workspace report names the stack; depth against a frame in the middle of it shows every other chain that frame participates in, which is what tells you whether collapsing a forwarding layer is safe or whether three other callers depend on it.
• Testing a "this looks misplaced" hunch. The caller trees show where the callable is really used from — the same evidence the possibly-misplaced finding is built on, in full rather than summarized.

Which one to reach for

What a scoped run measures

--directories narrows a run to the project directories it names, and the trace still follows calls out of them: a scoped run builds a program for each named project and for every project those projects' imports transitively reach — their dependency closure. So a call into another workspace package lands on a real frame, and the run reports frames, stacks, and per-project rows for packages it was never pointed at. That is the closure, not a leak.

How to read a depth that moved. A project's own tsconfig.json never lists the packages it imports, so a scoped run used to leave every call out of the named directory in code no traced project owned — and a call into unowned code is treated as external, a leaf, exactly like a call into an installed package. The stack ended at the package boundary and printed a plain number, with nothing in the report saying it had stopped early. A number that went up without an edit to explain it is that under-measurement being corrected.

Three things follow, and they are what a moved number should be checked against:

• A scoped depth is a measurement, not a floor. ≥ still means only an unfollowable call. Scope never printed one, which is exactly why a scoped under-measurement was invisible.
• The number does not depend on which run took it. A file is owned by the deepest project root containing it, whichever program pulled it in, so two scoped runs and the whole-workspace run agree about the same callable — provided each of them builds the project declaring it, which a refused destination's is not.
• A whole-workspace run's closure changes nothing. It names no directory, so every project is already a starting project and its closure is the workspace. A number that moved there moved for some other reason.

What a closure does not reach, and why each one is left out:

• Dependents, deliberately. The walk runs downward only. A project that imports the scoped one is not built and its stacks do not appear — which is what stops an edit in a dependent from moving the scoped project's numbers.
• A project root holding no package.json. A manifest is what makes a directory something another project can depend on; a root holding only a tsconfig.json is shared settings, read by every project rather than depended on by any. Without the rule, one such directory drags the whole workspace in.
• The workspace root. A project whose root contains every other project cannot be a meaningful dependency of any of them.

Both refusals apply to a destination only, so either kind is still traced in full when named directly or by a run that names no directory. What they cost is that a call into a refused directory resolves to no frame.

Both cross-project findings survive a downward-only scope, which is worth saying because it is not obvious. Module spread folds over a callable's transitive callees, which run downward — precisely what a closure holds in full. Possibly-misplaced compares a callable's callers within its own project, which a run always has whole whatever its scope. Neither needs a dependent.

Publishing does not widen with measurement. A ## 🔭 Callidescope section is written only for the projects a run was scoped to, so a scoped run never rewrites a section in a dependency it merely measured.

A worked example — the projects one real scoped run reaches, and why each — is examples/dependency-closure in the @callidescope/examples package.

What the graph does and does not contain

The same resolution rules govern all three commands, and they decide what any of them can tell you.

Four consequences worth holding on to:

• Structural matching is not optional, because classes routinely satisfy an interface without writing implements. It also means a caller list can contain a class that never actually calls the callable at runtime — check maximumImplementationCandidates when a result looks implausibly wide.
• A computed member call resolves to nothing. A caller reaching the callable that way will not appear, so breadth does not fully cover a rename in a codebase that dispatches through computed names.
• Calls into installed dependencies are leaves. Whether Array.prototype.map is deeply implemented says nothing about whether your layering is too deep, and counting it would move every number on an unrelated upgrade. A call into another project of the same workspace is not one of these — it resolves to a real frame, however the run was scoped.
• ignoreCallees globs are dropped from the graph entirely, so a callable the configuration ignores — typically a logger — appears in no list and counts toward nobody's depth or breadth.

Cycles are collapsed before depth is measured, so a mutually recursive cluster of three contributes three frames once — an honest floor on a stack that has no ceiling. That is why the numbers do not move between runs: detecting a repeat visit mid-walk would make the answer depend on which path arrived first, and a linter whose numbers move on its own is not usable as a gate.

Depth is only meaningful relative to a root, and most code in a framework codebase is called by the framework rather than by the repository. Roots are therefore configurable — decorated methods, lifecycle hooks, bootstraps, index exports — and anything left with no caller is promoted to an orphan root rather than dropped.

After reading

To narrow, gate, or publish a run, and to change any of the thresholds above, reach for the callidescope-configure skill. When a run fails or a report reads stale, reach for callidescope-triage.

A refactor moves the call graph, which makes every committed report stale. Re-run the write configuration once the change lands, and lint before regenerating: every frame carries a file:line, so a formatter that sorts class members moves the line numbers of everything after it, and a report written before that sort is stale the moment it lands.