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Author SHA1 Message Date
hermes
4c2f0acff3 fix(core): symmetric bandar thresholds; bandar needs all investors
- Basis points truncate toward zero instead of flooring, so a reading of
  -4.9952% stays neutral like its mirror image and -14.9952% stays
  distribution; tests cover both signs at both thresholds through
  bandar_tier. Goldens move by the rounding (BBCA top 5: -2426 -> -2425).
- With one investor side selected the summary has no total to weigh
  brokers against, so bandar and analyze_bandar reject it (INVALIDINPUT)
  instead of reading every tier as missing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V3syn2fN2LNo5pvTSqc6eh
2026-10-18 05:39:05 +00:00
hermes
970da26a0e feat: bandarmology (idx stocks bandar, analyze_bandar)
`idx stocks bandar SYMBOL...` reads the broker summary: for the top 1, 3,
5 and 10 brokers per side, buy value minus sell value in basis points of
value traded, with a signal from big accumulation to big distribution on
the headline tier (--top, default 5). Several symbols give a screen ranked
by that figure (at most 100, one request each), which pipes from
`stocks screen`. The MCP server exposes it as analyze_bandar (20 symbols).

- analysis/bandar.rs is pure and versioned (`top_concentration_v1`):
  integer basis points, no figure missing counted as zero, buy/sell VWAP
  from exact averages, and the brokers on both sides listed because their
  gross figures overstate their direction.
- Thresholds (±5%/±15%) follow fzn0x/idx (MIT); docs call them heuristics.
- Invalid input fails a screen at once; other errors fail one symbol and
  are warned about on stderr.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V3syn2fN2LNo5pvTSqc6eh
2026-10-18 05:34:37 +00:00