feat: increase max tool compression candidates from 5 to 15

devlog/2026-07-09_more-compression-candidates/REQ.md

@@ -0,0 +1,50 @@
+# REQ: Increase max tool compression candidates from 5 to 15
+
+## Background
+
+The context breakdown (shown when usage crosses the threshold) and the
+tool-output reminder nudge both surface a list of "largest ranges" to the
+model as compression candidates.
+
+Before this change:
+
+- `estimateContextComposition()` returned at most 10 message ranges and 5
+  tool-output ranges.
+- `injectCompressNudges()` sliced the top 5 from `largestRanges` when
+  building the tool-output reminder.
+
+Observation: the model was compressing too narrowly — frequently one
+message per `compress` call — because only a handful of candidates were
+visible at once. The compression philosophy in the system prompt asks the
+model to cover "the largest range you can in a single call (aim for 20+
+messages)", but the candidate list did not back that up.
+
+## Requirement
+
+Surface more compression candidates so the model can pick larger ranges:
+
+1. `estimateContextComposition()`:
+   - `largestRanges`: 10 → **15**
+   - `largestToolRanges`: 5 → **15**
+2. `injectCompressNudges()` tool-output reminder:
+   - `topRanges`: 5 → **15**
+
+Code and plain-text candidate lists (`largestCodeRanges`,
+`largestMessageRanges`) stay at 5 — they are informational, not the
+primary compression target.
+
+## Scope
+
+- `lib/messages/inject/utils.ts` (2 lines)
+- `lib/messages/inject/inject.ts` (1 line)
+
+No config, no persisted-state, no prompt-template changes.
+
+## Why split from PR #80
+
+This change was originally bundled into the `2026-07-09_summary-role-assistant`
+branch (Bug 39: compression summary role). PR #80 is pending review and
+cannot merge immediately, which blocks this independent improvement from
+shipping. Splitting it into its own PR lets both move forward independently.
+
+issue #13

devlog/2026-07-09_more-compression-candidates/WORKLOG.md

@@ -0,0 +1,32 @@
+# WORKLOG: more-compression-candidates
+
+## 2026-07-09
+
+### Implementation
+
+Cherry-picked commit `ea7db98` from `2026-07-09_summary-role-assistant`
+onto a fresh branch `2026-07-09_more-compression-candidates` based on
+`master` (`b8fba7a`).
+
+Changes (3 lines across 2 files):
+
+- `lib/messages/inject/utils.ts:652` — `perMessage.slice(0, 10)` →
+  `slice(0, 15)` (`largestRanges`)
+- `lib/messages/inject/utils.ts:653` — `perTool.slice(0, 5)` →
+  `slice(0, 15)` (`largestToolRanges`)
+- `lib/messages/inject/inject.ts:214` —
+  `composition.largestRanges.slice(0, 5)` → `slice(0, 15)`
+  (`toolOutputReminder` top ranges)
+
+### Verification
+
+- `npm run typecheck` — clean
+- `npm run build` — clean
+- Tests — green on the source branch (no test changes in this slice)
+
+### Files
+
+- `lib/messages/inject/utils.ts`
+- `lib/messages/inject/inject.ts`
+- `devlog/2026-07-09_more-compression-candidates/REQ.md`
+- `devlog/2026-07-09_more-compression-candidates/WORKLOG.md`

lib/messages/inject/inject.ts

@@ -211,7 +211,7 @@ export const injectCompressNudges = (
             const toolGrowth = composition.toolTokens - state.nudges.lastToolOutputNudgeTokens
             if (toolGrowth >= toolOutputThreshold) {
                 const fmt = (n: number) => (n >= 1000 ? `${(n / 1000).toFixed(1)}K` : String(n))
-                const topRanges = composition.largestRanges.slice(0, 5).map((r) => `${r.ref} (${fmt(r.tokens)})`).join(", ")
+                const topRanges = composition.largestRanges.slice(0, 15).map((r) => `${r.ref} (${fmt(r.tokens)})`).join(", ")
                 toolOutputReminder = `\n\n⚠️ ${fmt(toolGrowth)} new tool outputs accumulated (${fmt(composition.toolTokens)} total). Largest: ${topRanges}. Use compress tool to compress these ranges now.`
                 state.nudges.lastToolOutputNudgeTokens = composition.toolTokens
                 anchorsChanged = true

lib/messages/inject/utils.ts

@@ -649,8 +649,8 @@ export function estimateContextComposition(
         messageTokens,
         textTokens: Math.max(0, messageTokens - codeTokens),
         total: toolTokens + summaryTokens + messageTokens,
-        largestRanges: perMessage.slice(0, 10),
-        largestToolRanges: perTool.slice(0, 5),
+        largestRanges: perMessage.slice(0, 15),
+        largestToolRanges: perTool.slice(0, 15),
         largestCodeRanges: perCode.slice(0, 5),
         largestMessageRanges: perText.slice(0, 5),
     }