Module relevance 

Per-entry relevance metadata and CADMAS-CTX bucket projection.

Phase B foundation

The Liu et al. paper (arXiv:2512.22087) calls for a per-entry sidecar of relevance signals that an incremental derivation policy can score against the current task. The CADMAS-CTX paper (arXiv:2604.17950) independently needs a coarse context bucket z = (difficulty, dependency, tool_use) to key its per-(agent, skill, bucket) posteriors.

Both consumers share ~80 % of the extraction work — file paths, tool names, error-class markers — so this module emits a single RelevanceMeta that projects down to a Bucket via RelevanceMeta::project_bucket. Phase B’s DerivePolicy::Incremental and Phase C’s DelegationState both read from the same sidecar.

Scope in Phase B step 15

Extraction is pure and syntactic — no LLM calls, no IO. Heuristics:

• files: regex over text parts for path-like tokens.
• tools: names of ToolCall / ToolResult content parts.
• error_classes: leading tokens of common error markers (Error:, error[E, failed, panicked, traceback).
• explicit_refs: left for future turns-N-reference extraction (empty in this first cut).

Keeping it syntactic means the extractor can run in the append hot path (Session::add_message) without blocking.

Examples

use codetether_agent::provider::{ContentPart, Message, Role};
use codetether_agent::session::relevance::{Bucket, Dependency, Difficulty, RelevanceMeta, ToolUse, extract};

let msg = Message {
    role: Role::Assistant,
    content: vec![ContentPart::Text {
        text: "Edited src/lib.rs and tests/smoke.rs".to_string(),
    }],
};
let meta: RelevanceMeta = extract(&msg);
assert_eq!(meta.files.len(), 2);

let bucket: Bucket = meta.project_bucket();
assert_eq!(bucket.tool_use, ToolUse::No);
assert_eq!(bucket.dependency, Dependency::Chained);
assert_eq!(bucket.difficulty, Difficulty::Easy);

Structs

Bucket

Coarse context bucket — CADMAS-CTX Section 3.1.

RelevanceMeta

Per-entry syntactic relevance signals.

Enums

Dependency

CADMAS-CTX dependency axis.

Difficulty

CADMAS-CTX difficulty axis.

ToolUse

CADMAS-CTX tool-use axis.

Functions

bucket_for_messages

Project a coarse CADMAS-CTX bucket from a recent message window.

extract

Extract RelevanceMeta for a single chat-history entry.