headroom/tests/test_lossless_excluded_compaction.py
Tejas Chopra f0670404ce
feat(content-router): lossless-excluded compaction (grep/log/json) + enable in coding/general personas (#1762)
Builds on the now-merged personas (#1732). Two pieces:

### 1. Lossless compaction for EXCLUDED tool output
Excluded tools (Read/Grep/Glob/Write/Edit) stay out of *lossy*
compression, but their output is compacted by detected shape:
| shape | transform | guarantee |
|---|---|---|
| grep (SEARCH) | ripgrep --heading fold | **byte-lossless**
(`search_unheading` recovers) |
| log (BUILD_OUTPUT) | ANSI strip + run-collapse | **byte-lossless**
modulo non-semantic ANSI |
| json | whitespace-minify | **data-lossless** (`json.loads` equal), NOT
byte-exact |

Source code + glob path-lists → verbatim. grep gated on
`_try_detect_search` (the general/Magika classifier calls grep-over-code
SOURCE_CODE and would miss it). Off by default
(`compact_excluded_lossless`).

### 2. Enable it in the coding/general personas
`compact_excluded_lossless=True` on the coding + general profiles,
threaded via `proxy_env` + `proxy_pipeline_kwargs` + a per-request
`ContentRouter.apply` override. So `HEADROOM_SAVINGS_PROFILE=coding`
auto-folds excluded grep/log/json.

## Why
The coding persona was getting ~2.5% on OpenCode because its dominant
traffic (Grep/Read) is excluded, and RTK (shell-only, lossy) never sees
OpenCode's *native* tools. This recovers those savings losslessly.

## Measured (end-to-end via coding-persona kwargs, real `rg` output)
41,589 → 26,562 chars (**−36%**), `router:excluded:lossless_search`,
byte-recoverable.

## Accuracy
grep/log = byte-lossless → edit-safe. json = data-lossless (edit-caveat
for read-then-edit-JSON, documented). Read of source code → untouched
(tested).

47 tests (personas + all three tiers + persona-enablement + end-to-end).
ruff + mypy clean. **No personas duplication** — rebased onto main after
#1732 landed. Supersedes #1755.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
2026-07-03 12:09:05 -07:00

119 lines
3.9 KiB
Python

"""Information-preserving compaction for EXCLUDED tool output.
Excluded tools (Read/Grep/Glob/Write/Edit) are protected from *lossy*
compression for accuracy. This feature still compacts them by detected shape,
using only reversible / data-preserving transforms:
* SEARCH (grep) -> ripgrep --heading fold [byte-lossless]
* LOG -> ANSI strip + run-collapse [byte-lossless modulo ANSI color]
* JSON -> whitespace-minify [data-lossless; same object, NOT byte-exact]
Source code and glob path-lists match nothing -> untouched. Always on
(information-preserving, so it needs no feature gate) in every path.
"""
from __future__ import annotations
import json
import pytest
from headroom.providers import OpenAIProvider
from headroom.tokenizer import Tokenizer
from headroom.transforms.content_router import ContentRouter, ContentRouterConfig
from headroom.transforms.lossless_compaction import expand_runs, search_unheading, strip_ansi
GREP = "".join(
f"src/module_{f}.py:{ln * 3}:matched occurrence with some real content here\n"
for f in range(6)
for ln in range(15)
)
LOG = "".join(
f"\x1b[32m2026-07-03 INFO worker {i % 3} processing job batch\x1b[0m\n" for i in range(40)
)
LOG += "".join("2026-07-03 WARN transient retry, backing off\n" for _ in range(25))
JSON = json.dumps(
{"users": [{"id": i, "name": f"user{i}", "active": i % 2 == 0} for i in range(40)]},
indent=2,
)
CODE = "def foo(x):\n return x + 1\n\nclass Bar:\n value = 42\n" * 30
GLOB = "\n".join(f"src/module_{i}.py" for i in range(60)) + "\n"
@pytest.fixture
def tokenizer():
provider = OpenAIProvider()
return Tokenizer(provider.get_token_counter("gpt-4o"), "gpt-4o")
def _compact(content: str):
router = ContentRouter(ContentRouterConfig())
return router._lossless_compact_excluded(content)
# --- helper: right transform per shape, right guarantee ---
def test_grep_search_fold_is_byte_lossless():
out, kind = _compact(GREP)
assert kind == "search"
assert len(out) < len(GREP)
assert search_unheading(out) == GREP # byte-exact
def test_log_compaction_recovers_modulo_ansi():
out, kind = _compact(LOG)
assert kind == "log"
assert len(out) < len(LOG)
assert expand_runs(out) == strip_ansi(LOG) # recover the lines (ANSI dropped)
def test_json_minify_is_data_lossless():
out, kind = _compact(JSON)
assert kind == "json"
assert len(out) < len(JSON)
assert json.loads(out) == json.loads(JSON) # same object; NOT byte-exact
def test_source_and_glob_untouched():
assert _compact(CODE) is None
assert _compact(GLOB) is None
# --- end-to-end through the router pipeline (excluded tools) ---
def _run(content: str, tool: str, tokenizer):
router = ContentRouter(ContentRouterConfig())
messages = [
{
"role": "assistant",
"tool_calls": [{"id": "c1", "function": {"name": tool, "arguments": "{}"}}],
},
{"role": "tool", "tool_call_id": "c1", "content": content},
]
result = router.apply(messages, tokenizer, compress_user_messages=True)
return result.messages[1]["content"], result.transforms_applied
def test_pipeline_folds_grep_and_recovers(tokenizer):
out, transforms = _run(GREP, "grep", tokenizer)
assert "router:excluded:lossless_search" in transforms
assert search_unheading(out) == GREP
def test_pipeline_compacts_log_read(tokenizer):
out, transforms = _run(LOG, "read", tokenizer)
assert "router:excluded:lossless_log" in transforms
assert expand_runs(out) == strip_ansi(LOG)
def test_pipeline_minifies_json_read(tokenizer):
out, transforms = _run(JSON, "read", tokenizer)
assert "router:excluded:lossless_json" in transforms
assert json.loads(out) == json.loads(JSON) # data-lossless (same object)
def test_pipeline_leaves_source_read_untouched(tokenizer):
out, _ = _run(CODE, "read", tokenizer)
assert out == CODE