fix(tooling): summarise the whole list in the probe, and restore the field it hid

[eaitbrahim]

Closes #230.

D1 — shape_of only ever inspected results[0]

It reduced a list to [shape_of(value[0]), "... N items"], so every probe validated one element and reported a match for the whole collection. Live, trading_pairs returns 89 pairs in two distinct key-sets: 63 carry min_order_amount (BTC-USD 0.1 and ETH-USD among them), 26 do not — and results[0] is BILL-USD, one of the 26. The probe reported 5/5 and then 6/6 matched while blind to a field on 71% of pairs, including every asset keel trades.

shape_of now merges every element: the union of the keys, a key carried by only some of them marked min_order_amount (63/89), and a key the venue types inconsistently rendered Decimal|str (77 str, 12 Decimal) instead of silently taking the first. One summary row and a count come back however long the list is — an 89-pair response never prints 89 shapes.

How a partially present key compares against a fixture

A fixture is a single representative object and cannot express "63/89", so the convention is that the fixture carries the union of what a row can hold, and the count is reported as information rather than as a mismatch. rh_trading_pairs.json's one row is BTC-USD, and BTC-USD is sent the minimum, so:

• fixture omits min_order_amount → NEW AT VENUE results[].min_order_amount — the fix(brokers): read robinhood's real estimated_price shape, correct every fixture #218 regression, now catchable;
• fixture carries it → clean match, plus a printed note.

Mechanically: every note lives in a trailing (...) suffix on the shape token, and compare_shapes compares tokens with that suffix stripped. It rides on the key, so a partially present key whose value is an object is annotated the same way as one whose value is a leaf, and it survives --json verbatim. Treating partial presence as a difference instead would fail the trading_pairs probe on every run against a venue behaving exactly as measured — the same cry-wolf failure #217 F5 taught this script to avoid.

A mixed type is deliberately not bare-equal to either of its halves, so it still reports TYPE DIFFERS with both tallies in the message. At a venue already caught quoting the same kind of value two ways in one object (#217 F6), that is a finding, not a formatting detail.

The report, on the measured 63/26 split

=== trading_pairs ===
  shape matches rh_trading_pairs.json
  note: results[].min_order_amount  present on 63/89 elements

and in --json:

"results": [
  {
    "asset_code": "str",
    "asset_increment": "str",
    "is_api_tradable": "bool",
    "max_order_size": "str",
    "min_order_amount (63/89)": "str",
    "quote_code": "str",
    "quote_increment": "str",
    "status": "str",
    "symbol": "str"
  },
  "... 89 items"
]

That exact run — 89 rows, BILL-USD first, 63 carrying the key — is asserted end to end in test_the_real_63_of_89_split_matches_the_fixture_and_is_reported, including exit code 0 and the note line.

D2 — the regression

min_order_amount is restored to tests/fixtures/rh_trading_pairs.json with BTC-USD's real 0.1. The row's max_order_size is corrected to the measured 20.0000000000000000 at the same time (it read 10.00000000); the increments were already correct.

The false claim is corrected in packages/keel-broker-robinhood/README.md (§ "No published minimum order size" → "The minimum order size is published, but only on some pairs"), in RobinhoodTransport.get_trading_pairs' docstring, and in the two suite tests that asserted the field's absence. Dated documents under docs/experiments/ are left alone. #198's prerequisite list still needs its comment corrected — min_order_amount is a lower-bound source for every asset keel trades, read as optional per pair.

D3 — regression test

test_a_key_only_a_LATER_element_carries_is_still_reported. Against the old shape_of:

>       assert len(diffs) == 1, f"a key only the second element carries went unreported: {diffs}"
E       AssertionError: a key only the second element carries went unreported: []
E       assert 0 == 1
E        +  where 0 = len([])

tests/scripts/test_robinhood_smoke.py:178: AssertionError
1 failed, 31 deselected in 0.05s

Also

The module docstring's shape-validation claim is now true and scoped: a run corroborates only what the account's own data exercises, and no report line distinguishes "the venue has no such field" from "this account produced no row carrying it". The orders probe on an account with no crypto history still proves path, signature and envelope only, never field names.

The read-only guarantee is untouched — _ReadOnly still installs the GET-only guard onto _request, and test_running_every_probe_issues_only_gets (including the probes-actually-succeeded assertion) passes unchanged.

Gates

$ uv run ruff check keel tests packages scripts
All checks passed!

$ uv run mypy
Success: no issues found in 219 source files

$ uv run pytest -q
2455 passed, 1 skipped in 36.99s
SKIPPED [1] packages/keel-broker-api/keel_broker_api/conformance/suite.py:254: adapter serves no granularity the suite could exercise

2444 → 2455 is the 11 tests added here; the one skip is the expected conformance candles probe.

Not run live — this branch has no credential. The proof is in the tests; a live re-run against the venue is yours.

References #218 (removed the field) and #198 (carries the false claim).

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