`_fetch_limit` had no test: a text query over-fetches `limit * 10` only with a
reranker, and an image query keeps its vector ranking either way. The sandbox
test asserted `KeyError`, which `UnknownDatabaseError` subclasses, so it could
not tell the contract from a bare one.
`uses_configured_databases` documents a mapping of one as covered; the test
named for it passed no mapping at all. Its `config` parameter is an `AppConfig`.
`test_an_analysis_capability_mounts_the_configured_set` carried a VCR marker and
no cassette, making no HTTP calls.
Search results and capsule entries name the collection they came from; the
images attached beside them carried only the chunk id and reference. Two
collections can return the same picture of the same document, so the two
labels were identical and the model could place neither.
The decision is the one already made for the text: `covers_multiple` at the
generic search tool, and the flag `search_corpus` computed for the capability
tools, which it now returns.
A name nothing covers raised `KeyError` in four places and
`AmbiguousDatabaseError` in a fifth, so a caller had to catch both and neither
name said what happened. `UnknownDatabaseError` is all of them, exported from
`haiku.rag.store` beside the other errors.
It subclasses `KeyError`, since selecting by name is a lookup, and prints its
message plainly rather than quoted as a missing key. Both CLIs turn it into the
same clean exit they already gave the others.
`ask(sources=["typo"])` reached the model, which discovered the name only if it
searched: requests spent on a selection that could never answer, and a run that
never searched answered anyway.
Checked by name, not by opening: a client covering a set opens a database when a
query reaches it, and validating by opening would open every one of them before
any search, letting a database nobody asked about fail the run.
`create_mcp_server` promised one database and accepted a scope covering a set,
where the write tools exist and fail on use. It refuses that now.
Resolving is the public factory's job, as it is `HaikuRAG`'s: `_covering` takes
a scope someone already resolved, so the configured name survives without a
`DatabaseScope` reaching the public signature.
The test that a scope decides the database asserted `all(...)` over a search
that could return nothing, which held whatever the server read. It reads the
listing instead, so alpha's documents being present and beta's absent both have
to be true.
The test searched through the capability, which embeds the query, so it passed
against a local Ollama and failed CI where there is none. What it exists to show
is that a lent client is what the capability reads through: `_ensure_rag`
returns it, and a full-text search through it names its results.
`reader_for` returned itself before looking at the name, so an "alpha" client
answered `reader_for("beta")` with alpha's reader. A citation naming another
database would have been read from the wrong one.
Both paths decide through `clients_covering` now, so one database refuses a
wrong name the way a set already did.
The chat citation test said mounting lends the client without showing it; a
chat test shows it and the docstring points there.
`reader_for` documented None as covering any database it could not place, but a
name outside the set raises `KeyError` like `clients_for` does: provenance
naming a database this client does not cover is wrong rather than absent. None
means one thing, a federated client given no name.
`sources=[]` means two things. On a search it selects nothing to search; on the
constructor it raises, since a client over no database can do nothing. Both are
written down now.
A capability reads through a lent client, so what a citation records is that
client's database and not the scope the capability was built with. Chat lends
one, and had no test saying so.
`format_for_agent` named the database whenever one was named, so a search over
a single named database carried a line with nothing to distinguish. It now takes
`include_collection` from the caller, which decides from the search selection
rather than from the hits: a search that could have drawn on two collections
names them even when everything came back from one.
`Collection:` at the model boundary, database in configuration and
administration. `source` on results, documents, citations and analysis
dictionaries is unchanged.
Two files of 1,405 and 814 lines become seven: scope resolution, lifecycle,
search, documents, expansion, citations and capabilities. `_config`, `_seed`
and the rest move to `helpers.py`, importable by the sandbox tests that share
them, and the package points VCR back at `tests/cassettes/multi_db/`.
