| name | yahoo-fantasy |
| description | Analyze your Yahoo Fantasy sports team, evaluate roster health, compare free agents, and recommend add/drop moves. Use when user asks about fantasy team, waiver wire, roster moves, or player analysis. |
Yahoo Fantasy Team Analyzer
Comprehensive analysis of the user's Yahoo Fantasy team with actionable roster moves.
Opt-in deep-dive phases
Load these detail files ONLY when the user's request triggers them. Skip otherwise — web searches are expensive.
| Trigger keywords | Load file |
|---|
| "深度分析" / "advanced stats" / "regression" / "xStats" / "dig into [player]" | phases/advanced-metrics.md |
| "找潛力新秀" / "breakout" / "prospect" / "rookie" / "young player" | phases/breakout-scanner.md |
Phase 1: Auth & league discovery
Call get_leagues. On auth error: authenticate (no args) → user pastes code= from redirect → authenticate(code=...) → retry.
If multiple leagues, ask which. Record league_key and my_team_key.
League settings (canonical cat list): get_league_settings(league_key) returns stat_categories with stat_id → display_name and sort_order (1 = higher better, 0 = lower better). Use this — don't hardcode or guess cats. Feeds Phase 4 matchup diff and Phase 7 category-fit rubric.
Player key lookup: search_players(league_key, name="...") returns player_key for stats calls. Never guess keys.
Phase 2: Roster analysis
2a. Week range
get_matchup(team_key) → week_start, week_end.
2b. Daily lineup scan
For each day in range, parallel-call get_roster(team_key, date="YYYY-MM-DD"). Per player per day record: selected_position, is_bench, is_injured_reserve.
2c. Schedule verification (avoid flagging off-days)
Cross-reference GP from Phase 3's lastweek result: if GP < active days, the gap is team off-days — not a lineup mistake. No extra API needed.
Flag decision table:
| Situation | Flag? |
|---|
| BN + team had game + player was scheduled to play/start | Yes |
| BN + team had game + player not scheduled (e.g. SP on non-start day) | No — correct |
| BN + team had no game | No — off-day |
BN + is_injured_reserve: true | No — IL slot is separate |
| DTD player active at risk | Yes |
| NFL bye-week player in active slot | Yes |
| NA-status player in active slot | Yes — blocks the slot |
| Pitcher in P slot vs SP/RP slot | No — stats score identically |
2d. Today's lineup check
get_roster(team_key) (no date = today).
For every is_bench: true, is_injured_reserve: false:
- Hitter: flag if clearly stronger than active player at an eligible position
- Pitcher: flag only if confirmed start (SP) or save/hold opp (RP) today
- NA in active slot: always flag
Output per flag:
- Hitter:
SWAP: [BN player] → [slot], bench [active player]
- NA:
MOVE: [NA player] out of [slot] → BN, activate [BN player]
Phase 3: Player stats
Batch all rostered players in 2 parallel calls:
get_roster_stats(team_key, stat_period="lastweek")
get_roster_stats(team_key, stat_period="season")
get_roster_stats accepts season | lastweek | last30. last14 is NOT supported. last30 returns HTTP 400 in the first ~2 weeks of the season — skip if it fails.
Single-player fallback: get_player_stats(player_key, stat_period=..., date=...). Periods: season | week | lastweek | last14 | last30 | date (date requires date="YYYY-MM-DD").
Identify:
- Underperformers: lastweek >20% below season in key cats
- Hot streaks: lastweek well above season average
Phase 4: Current matchup
Reuse get_matchup from 2a. Note: score vs opp, cats ahead/behind, cats still live, streaming opportunities.
Phase 5: Free agents
get_free_agents(league_key, position="...", include_stats=true)
include_stats=true avoids separate stats calls. count must be an int — omit to use default (25).
Priority positions: injured spots, underperforming starters, streaming slots (RP in MLB, flex).
Ownership trend (percent_owned + percent_owned_delta):
- Rising >10% WoW → market sees breakout, act fast
- Falling >10% WoW but production still solid → possible dip-buy
Phase 6: News verification
Web search for: injured rostered players (return timeline), top FA candidates, unusual stat drops (role change / trade rumor).
Pattern: "[Player Name]" fantasy [sport] news injury
Yahoo injury status can lag — news is authoritative.
Phase 7: Scoring & report
Every add/drop candidate gets a composite 0–100 score so trade-offs are explicit. Trust the tier, not 2-point gaps — inputs include estimation.
Composite score
| Dimension | Weight | Notes |
|---|
| Category fit (live matchup / team cat needs) | 25 | See rubric below — dominant factor |
| Production vs replacement | 20 | Season stats vs median FA at same position |
| Role / opportunity | 15 | Starter lock, closer role, bell-cow, target share secured |
| Trend | 15 | lastweek vs season; direction over last 14–30 days |
| Underlying agreement | 10 | xStats vs surface — ONLY if advanced-metrics phase ran |
| Positional scarcity | 10 | C / SS / TE → full 10; OF / WR / RP → 3–5 |
| Schedule | 5 | Games left this week; ROS opponent strength |
If advanced-metrics did NOT run, rescale remaining weights ×100/90 so max stays 100.
Category fit rubric (0–25)
This is what turns "good player" into "good FOR US, THIS WEEK". For each scoring cat in your league:
- Get current matchup gap (you − opponent) from Phase 4.
- Project the player's contribution this week (season rate × games remaining).
- Apply matchup-state multiplier:
| Cat state | Multiplier |
|---|
| Tight, gap ≤ 2 — swing cat | ×3 |
| Behind 3–5, games remain | ×1.5 |
| Leading 3–5 | ×1.0 |
| Locked (ahead ≥ 6, OR behind ≥ 6 with no games left) | ×0.2 |
Negative cats (ERA, WHIP, NBA TO): invert direction — a high-ERA pitcher actively hurts when you lead ERA.
Sum weighted contributions across all cats → normalize to 0–25.
Special cases:
- ROS / season-long questions (no live matchup): substitute matchup-state with your team's season cat ranks — bottom-3 ranks ×2, top-3 ×0.5.
- H2H-points / rotisserie leagues: collapse cat fit to "projected points / z-score". No matchup multipliers.
Tiers & swap threshold
| Score | Tier | Action |
|---|
| 85+ | Must add | drop almost anyone |
| 70–84 | High priority | drop weakest bench / cold player |
| 55–69 | Solid | add if clear drop candidate exists |
| 40–54 | Streamer / watch | weekly plug-ins or injury cover only |
| <40 | Pass | |
Recommend a swap only if ADD − DROP ≥ 15. Smaller gaps = churn, don't move.
Report layout
Roster health block:
ROSTER
Active healthy: ...
Day-to-day: ... (injury note)
IL/Injured: ... (return ETA, stash-worthy?)
Cold: ...
Hot: ...
Regression watch: ... (only if advanced-metrics ran)
Scored move block (full breakdown for top 3, one-liner for rest):
ADD: [Player] ([Pos]) — [team] Score: XX (Tier)
DROP: [Player] ([Pos]) — [team] Score: YY (Tier)
Gap: +Z
Breakdown — ADD:
Cat fit 22/25 (swings SB +3, HR +1)
Production 15/20
Role 14/15
Trend 11/15
Underlying 7/10
Scarcity 3/10
Schedule 5/5
Why ADD: [one line]
Why DROP: [one line]
Risk: Low | Med | High — [reason]
One-liner for lower-priority candidates: ADD X (72) / DROP Y (58) — gap 14, skip.
Streaming (if applicable)
MLB 2-start SPs, NBA back-to-back plays, NFL favorable matchups. Score using only Category fit + Schedule — short-term plays; other dimensions don't apply.
Sport-specific cheat sheet
MLB
- SP core: ERA, WHIP, K/9, W, QS
- RP core: SV, HLD, ERA, WHIP
- Bats core: AVG, HR, RBI, R, SB
- Drop: ERA > 5.00 (SP), AVG < .220 no power, lost closer role
- Add: new closer, 10+ day hot streak, call-up getting starts
- IL stash: IL slots are separate — hold high-upside injured players
NBA
- Core: PTS, REB, AST, STL, BLK, 3PM, FG%, FT%, TO (neg)
- Drop: bench role, minutes restriction, cold 2+ weeks no role security
- Add: injury-driven promotion, usage/minutes uptick, favorable b2b
NFL
- QB: pass yds/TD, rush, INT (neg)
- RB: rush yds/TD, rec, snap %, target share
- WR/TE: targets, receptions, yds, TD, air yards
- Drop: lost WR1 role, RB committee reduction, offense collapsing
- Add: handcuff after starter injury, emerging target share, favorable ROS
Final output structure
- Quick summary (3–5 bullets) — include 1–2 line callout of which cats are swing cats this week
- Roster status table
- Top 3 scored moves (full breakdown) + one-liners for the next 3–5
- Watch list
- This week's focus
Keep it actionable. Injuries and significant underperformance > marginal upgrades.
