[rubas-agent]

Before

Probe on origin/main, with %Kagi.Client{session_token: "t"}:

{:search, ["x", [site: %{a: 1}]], {:raised, Protocol.UndefinedError}}
{:search, ["x", [region: %{a: 1}]], {:raised, Protocol.UndefinedError}}
{:summarize, ["https://a", [lang: %{}]], {:raised, Protocol.UndefinedError}}
{:search, ["x", [from: "2024-13-45"]], {:error, :http_error, "HTTP 302"}}
{:search, ["x", [verbatim: "false"]], {:error, :http_error, "HTTP 302"}}

The last two reached the network. verbatim: "false" sent verbatim=1.

Problem

AGENTS.md says that a public function without a bang returns {:ok, struct} or {:error, %Kagi.Error{}}. Kagi.search and Kagi.summarize raise on a map in :site, :filetype, :region, or :lang. They also send bad values: any truthy :verbatim turns verbatim on. The date regex accepts "2024-01-01\n", "2024-13-45", and a :from after :to.

After

The same probe on this branch:

{:search, ["x", [site: %{a: 1}]],
 {:error, :invalid_option, ":site must be a non-empty string, got: %{a: 1}"}}
{:search, ["x", [region: %{a: 1}]],
 {:error, :invalid_option, ":region must be a non-empty string, got: %{a: 1}"}}
{:summarize, ["https://a", [lang: %{}]],
 {:error, :invalid_option, ":lang must be a non-empty string, got: %{}"}}
{:search, ["x", [from: "2024-13-45"]],
 {:error, :invalid_option,
  ":from must be a YYYY-MM-DD date, got: \"2024-13-45\""}}
{:search, ["x", [verbatim: "false"]],
 {:error, :invalid_option, ":verbatim must be a boolean, got: \"false\""}}

No call sends a request. The README now says that :from must not be after :to.

Cause, design, tests

Cause.

• lib/kagi/search.ex:append_filter/3 interpolates :site and :filetype into the query, so a map raises Protocol.UndefinedError.
• lib/kagi/search.ex:query_params/2 passes :region unchecked to the Req params.
• lib/kagi/summary.ex:query_params/2 passes :lang unchecked as target_language.
• lib/kagi/search.ex:validate_date/2 used ~r/^\d{4}-\d{2}-\d{2}$/. $ matches before a trailing newline, and the regex does not check that the date exists.

Design.

• Kagi.Search.validate_options/1 now runs before build_query/2, so append_filter/3 only sees valid values. One validate_string/2 checks :site, :filetype, and :region (nil or a non-empty binary). validate_verbatim/1 accepts nil or a boolean.
• parse_date/2 parses :from and :to with Date.from_iso8601/1, and validate_date_order/2 rejects :from after :to. The request still carries the original string. The regex is gone.
• Kagi.Summary.target_language/1 checks :lang (default "EN").
• Unknown option keys still pass. Rejecting them is a breaking change for another PR. lib/kagi/http.ex, CHANGELOG.md, and the version do not change.

Tests. test/kagi/search_test.exs:

• rejects a :site, :filetype, or :region that is not a non-empty string before any request
• rejects a :verbatim that is not a boolean
• rejects :from with a trailing newline, an impossible date 2024-13-45, and a range where :from is after :to
• accepts a valid :from/:to range and sends from_date and to_date unchanged

test/kagi/summary_test.exs: rejects a :lang that is not a non-empty string.

A fake adapter sends a message to the test pid, and refute_received proves that no request went out.

MIX_ENV=test: mix compile --warnings-as-errors, mix format --check-formatted, mix credo --strict, and mix dialyzer are clean. mix test: 59 passed, 3 excluded (live).