Crate boundgraph_slice 

Layer 4 of BoundGraph: the slicers that make context cost linear.

A raw tool result might be ten thousand lines. What the next step receives is a few hundred tokens of structured summary — a Condensate — while the original stays addressable in the content store for an auditor. That single move is what turns quadratic context growth into linear growth, and it is the mechanism behind Law II.

Why naive truncation is not an option

Cutting the first n bytes off a result is cheap and almost always wrong. The interesting part of a build log is at the end; the interesting part of a diff is spread across hunks; the interesting part of a JSON response is its shape, not its first field. Worse, a truncated result looks complete — it invites confidently wrong conclusions, which is precisely the failure mode this project exists to prevent.

So slicing is per-kind and structure-aware. Each slicer knows what is worth keeping in its own format, and every one of them reports honestly whether it dropped anything.

The contract

Slicer::condense is a provided method that preserves the original, calls the implementation, and then checks the result against the cap. An implementation cannot skip any of those, so “output never exceeds the cap” is a property of the trait rather than a promise each slicer makes separately. See slicer for the reasoning.

Status

Feature 07, milestone M3. Built in dependency order rather than story order, because US-0702 degrades to US-0703’s slicer and so needs it first:

Story	Module
US-0701 slicer trait	slicer
US-0703 log slicer	log
US-0704 diff slicer	diff
US-0705 JSON slicer	json
US-0702 AST slicer	ast (feature ast)

Re-exports

pub use ast::AstSlicer;

pub use ast::Language;

pub use diff::DiffSlicer;

pub use diff::FileDiff;

pub use diff::FileStatus;

pub use diff::Hunk;

pub use json::JsonSlicer;

pub use json::REDACTED;

pub use log::Level;

pub use log::LogLine;

pub use log::LogSlicer;

pub use slicer::ByteCeiling;

pub use slicer::CommandOutcome;

pub use slicer::Estimate;

pub use slicer::MemoryStore;

pub use slicer::Raw;

pub use slicer::Slice;

pub use slicer::SliceError;

pub use slicer::Slicer;

pub use slicer::Store;

pub use slicer::StoreError;

pub use slicer::TokenCount;

Modules

ast

Condensing source code: keep the shape, elide the bodies.

diff

Condensing patches: whole hunks, or none of them.

json

Condensing JSON: keep the shape, sample the values.

log

Condensing command output: keep what failed, drop what scrolled past.

slicer

The contract every slicer meets, and the machinery that makes it hold.

Structs

SchemaId

Re-exported so a consumer naming a slicer does not also depend on boundgraph-core just for its identifier. Names the shape of a condensate’s payload.

SlicerId

Re-exported so a consumer naming a slicer does not also depend on boundgraph-core just for its identifier. Which slicer produced a condensate, and at what version.