PR #574: League constants 60/40 blend (2026/2025) — May 15 mid-season update by jaayslaughter-cpu · Pull Request #443 · jaayslaughter-cpu/mework

jaayslaughter-cpu · 2026-05-15T17:03:13Z

League Constants — 60/40 Blend (2026 Actuals / 2025 Reference)

Source: Baseball Reference totals through May 14, 2026 (49,542 PA, 30 teams × ~44 games)

What changed

Constant	2026 Actual	Blended (60/40)	Was in code
wOBA	.307	.310	.308/.320
OBP	.319	.317	.315
SLG	.389	.397	.410
AVG	.240	.241	.245
ISO	.149	.155	.156
BABIP	.288	.292	.288
ERA	4.10	4.12	4.10
K%	22.2%	22.4%	22.8%
BB%	9.5%	9.1%	8.3-8.7% ABS effect
O-swing	~28.5%	28.7%	31.6% large drop — ABS robot ump
HR-FB%	~10.5%	10.9%	11.9%

Notable: BB% is up in 2026 (ABS challenge system). O-swing drops from .316 to .287 — batters disciplined vs machine-called strikes.

Files updated (7)

fangraphs_layer.py — LEAGUE_DEFAULTS pitcher+batter
prop_enrichment_layer.py — _get_fg_batter/pitcher defaults + chase fallbacks
pa_model.py — LEAGUE_RATES K/BB/HR/2B/1B/OUT block
lineup_chase_layer.py — _LEAGUE_O_SWING + _LEAGUE_K_PCT
tasklets.py — league avg dict + slg/bb_pct/k_pct fallbacks
streak_agent.py — woba/fip reference baselines
data/calibration_params.json — league_constants section added

Summary by cubic

Updates MLB league constants to a 60/40 blend of 2026 actuals and 2025 reference (through May 14) and applies them across models and fallbacks. Centralizes the values in data/calibration_params.json for easier future updates.

New Features
- Added league_constants to data/calibration_params.json (wOBA 0.310, OBP 0.317, SLG 0.397, AVG 0.241, ISO 0.155, BABIP 0.292, K% 0.224, BB% 0.091, ERA 4.12, HR/FB% 0.109, O-swing 0.287).
- Updated defaults/baselines in fangraphs_layer, pa_model, lineup_chase_layer, prop_enrichment_layer, streak_agent, and tasklets (e.g., K 22.4%, BB 9.1%, O-swing 28.7%, SLG 0.397).
- Refreshed PA outcome rates (HR 3.0%, 2B 4.4%, 1B 14.1%, OUT 45.5% residual) and tuned streak/chase logic to the ABS-influenced run environment.

^{Written for commit 6607658. Summary will update on new commits. Review in cubic}

Summary by CodeRabbit

Chores
- Updated 2025 MLB season baseline statistical constants across the system, including league-average rates for pitcher and batter performance metrics used in probability calculations and predictions.
- Refreshed default fallback values for when live statistical data is unavailable, ensuring calculations remain current with latest seasonal baselines.

ecc-tools · 2026-05-15T17:03:20Z

ECC bundle files are already tracked in this repository. Skipping generation of another bundle PR.

coderabbitai · 2026-05-15T17:04:11Z

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 77578952-68a7-4bbf-aa61-388161f93314

📥 Commits

Reviewing files that changed from the base of the PR and between 52e9c24 and 6607658.

📒 Files selected for processing (7)

data/calibration_params.json
fangraphs_layer.py
lineup_chase_layer.py
pa_model.py
prop_enrichment_layer.py
streak_agent.py
tasklets.py

📝 Walkthrough

Walkthrough

This PR updates league-average baseline constants used as fallbacks throughout the prediction and enrichment pipeline, applying a 60/40 2026/2025 season blend calibration. Changes span seven files: a new calibration reference, base PA outcome rates, FanGraphs defaults for pitchers and batters, probability adjustment baselines, and feature normalization constants.

Changes

League Baseline Calibration Update

Layer / File(s)	Summary
Calibration source and base league rates `data/calibration_params.json`, `pa_model.py`	New `league_constants` reference section documents the 60/40 blend, and `LEAGUE_RATES` constants for strikeout/walk/home-run/double/single outcome rates are updated to match the blended model.
FanGraphs pitcher and batter fallback defaults and adjustments `fangraphs_layer.py`, `streak_agent.py`	`LEAGUE_DEFAULTS` pitcher and batter fallback statistics (wOBA, K-BB%, FIP, ERA, BABIP, etc.) are updated; pitcher and batter probability delta baselines in `streak_agent.py` shift to use new FIP (4.12) and wOBA (0.310) targets.
Enrichment and feature vector baseline constants `lineup_chase_layer.py`, `prop_enrichment_layer.py`, `tasklets.py`	Chase score league baselines (O-swing, K%) and pitcher/batter enrichment fallback stats are updated; platoon priors and XGBoost feature vector normalization constants (SLG, BB%, K%) are adjusted.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

jaayslaughter-cpu/mework#290: Prior update to the same league-average fallback constants in fangraphs_layer.py, lineup_chase_layer.py, and related prediction layers.
jaayslaughter-cpu/mework#318: Earlier calibration update affecting the same fallback constants and feature baselines across fangraphs_layer.py, prop_enrichment_layer.py, and tasklets.py.
jaayslaughter-cpu/mework#408: Concurrent updates to prop_enrichment_layer.py's missing-stats enrichment fallback behavior and chase-score fallback logic.

Poem

🐰 Constants shift as seasons blend,
Sixty-forty split to mend,
From May's snapshot, baselines fly,
New odds and deltas multiply! ✨

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch pr-574-league-constants-blend

Tip

💬 Introducing Slack Agent: The best way for teams to turn conversations into code.

Slack Agent is built on CodeRabbit's deep understanding of your code, so your team can collaborate across the entire SDLC without losing context.

Generate code and open pull requests
Plan features and break down work
Investigate incidents and troubleshoot customer tickets together
Automate recurring tasks and respond to alerts with triggers
Summarize progress and report instantly

Built for teams:

Shared memory across your entire org—no repeating context
Per-thread sandboxes to safely plan and execute work
Governance built-in—scoped access, auditability, and budget controls

One agent for your entire SDLC. Right inside Slack.

👉 Get started

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

codacy-production · 2026-05-15T17:04:26Z

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Metrics 0 complexity

Metric Results

Complexity 0

View in Codacy

_{NEW Get contextual insights on your PRs based on Codacy's metrics, along with PR and Jira context, without leaving GitHub. Enable AI reviewer}
_{TIP This summary will be updated as you push new changes.}

deepsource-io · 2026-05-15T17:04:35Z

DeepSource Code Review

We reviewed changes in 52e9c24...6607658 on this pull request. Below is the summary for the review, and you can see the individual issues we found as inline review comments.

See full review on DeepSource ↗

PR Report Card

Overall Grade	Security Reliability Complexity Hygiene

Code Review Summary

Analyzer	Updated (UTC)	Details
Docker	May 15, 2026 5:04p.m.	Review ↗
JavaScript	May 15, 2026 5:04p.m.	Review ↗
Python	May 15, 2026 5:04p.m.	Review ↗
SQL	May 15, 2026 5:04p.m.	Review ↗
Secrets	May 15, 2026 5:04p.m.	Review ↗

Important

AI Review is run only on demand for your team. We're only showing results of static analysis review right now. To trigger AI Review, comment @deepsourcebot review on this thread.

gemini-code-assist

Code Review

This pull request updates league-average baseline constants across the codebase—including fangraphs_layer.py, pa_model.py, and tasklets.py—to reflect a 60/40 blend of 2026 and 2025 data. Review feedback identifies several locations where fallback values for metrics like era, xfip, and babip remain inconsistent with the new standards. Additionally, the reviewer noted that normalization logic in tasklets.py needs adjustment to align with the updated averages and suggested formatting woba to three decimal places for consistency.

gemini-code-assist · 2026-05-15T17:06:10Z

            "xfip":         stats.get("xfip",      4.06),
            "siera":        stats.get("siera",     4.06),
-            "k_bb_pct":     stats.get("k_bb_pct",  0.139),
+            "k_bb_pct":     stats.get("k_bb_pct",  0.133),


While k_bb_pct has been updated to 0.133, several other league fallbacks in this block (and throughout the file) remain inconsistent with the new blended constants. Specifically, era, xfip, and siera (lines 212, 216, 217) are still using 4.06 instead of the new 4.12 standard defined in fangraphs_layer.py and streak_agent.py. Additionally, babip (line 241) and z_contact (line 243) fallbacks in the batter block are also inconsistent with the updated defaults.

gemini-code-assist · 2026-05-15T17:06:11Z

            # slot 2: SLG for TB/power props (16% feature importance)
            if _is_tb_prop:
-                _slg = float(prop.get("slg", 0.410) or 0.410)
+                _slg = float(prop.get("slg", 0.397) or 0.397)


The update of the slg fallback to 0.397 creates an inconsistency with the normalization logic in the following line (3150). The calculation (_slg - 0.250) / 0.400 and the associated comment 0.410=avg(0.40) are based on the previous league average. To maintain the same feature scaling for an "average" player, the normalization constants should be adjusted. Similarly, the babip fallback in line 3152 remains at 0.288 instead of the new 0.292 standard.

gemini-code-assist · 2026-05-15T17:06:11Z

+  "notes": "prop_min_prob_overrides: per-prop MIN_PROB gates stricter than global 0.57. fantasy_score set to 0.99 (effectively excluded). hits_allowed excluded pending more data (Brier 0.4531).",
+  "league_constants": {
+    "_comment": "60/40 blend 2026/2025 \u2014 May 15 2026. Source: BBRef totals through May 14.",
+    "woba": 0.31,


For consistency with the other league constants in this file (which use three decimal places), woba should be explicitly set to 0.310.

Suggested change

"woba": 0.31,

"woba": 0.310,

deepsource-io · 2026-05-15T17:06:41Z

+    "1B":  0.141,   # single — blended (2026: 14.0%, 2025: 14.3%)
+    "OUT": 0.455,   # field out — residual to sum=1.000
 }
 assert abs(sum(LEAGUE_RATES.values()) - 1.0) < 0.01, "LEAGUE_RATES must sum to 1"


Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.

Usage of assert statement in application logic is discouraged. assert is removed with compiling to optimized byte code. Consider raising an exception instead. Ideally, assert statement should be used only in tests.

PR #574: League constants 60/40 blend (2026/2025) — May 15 update

6607658

jaayslaughter-cpu merged commit b6f450e into main May 15, 2026
2 of 4 checks passed

gemini-code-assist Bot reviewed May 15, 2026

View reviewed changes

deepsource-io Bot reviewed May 15, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

PR #574: League constants 60/40 blend (2026/2025) — May 15 mid-season update#443

PR #574: League constants 60/40 blend (2026/2025) — May 15 mid-season update#443
jaayslaughter-cpu merged 1 commit into
mainfrom
pr-574-league-constants-blend

jaayslaughter-cpu commented May 15, 2026 •

edited by coderabbitai Bot

Loading

Uh oh!

ecc-tools Bot commented May 15, 2026

Uh oh!

Uh oh!

coderabbitai Bot commented May 15, 2026 •

edited

Loading

Review failed

Walkthrough

Changes

Estimated code review effort

Possibly related PRs

Poem

Uh oh!

codacy-production Bot commented May 15, 2026

Uh oh!

deepsource-io Bot commented May 15, 2026 •

edited

Loading

Uh oh!

gemini-code-assist Bot left a comment

Uh oh!

gemini-code-assist Bot May 15, 2026

Uh oh!

gemini-code-assist Bot May 15, 2026

Uh oh!

gemini-code-assist Bot May 15, 2026

Uh oh!

deepsource-io Bot May 15, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Conversation

jaayslaughter-cpu commented May 15, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

League Constants — 60/40 Blend (2026 Actuals / 2025 Reference)

What changed

Files updated (7)

Summary by cubic

Summary by CodeRabbit

Uh oh!

ecc-tools Bot commented May 15, 2026

Uh oh!

Uh oh!

coderabbitai Bot commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Review failed

Walkthrough

Changes

Estimated code review effort

Possibly related PRs

Poem

Uh oh!

codacy-production Bot commented May 15, 2026

Up to standards ✅

Uh oh!

deepsource-io Bot commented May 15, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

DeepSource Code Review

PR Report Card

Code Review Summary

Uh oh!

gemini-code-assist Bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

gemini-code-assist Bot May 15, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot May 15, 2026

Choose a reason for hiding this comment

Uh oh!

gemini-code-assist Bot May 15, 2026

Choose a reason for hiding this comment

Uh oh!

deepsource-io Bot May 15, 2026

Choose a reason for hiding this comment

Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

jaayslaughter-cpu commented May 15, 2026 •

edited by coderabbitai Bot

Loading

coderabbitai Bot commented May 15, 2026 •

edited

Loading

deepsource-io Bot commented May 15, 2026 •

edited

Loading