**Executes the task on the real websites** (the search, the price check, the availability lookup, the configurator, the booking flow) and returns what came back. Runs a script you authored against the `get_library` vocabulary, on the live sites, and returns `{ ok, result, logs, error, ms }`. Call `get_library` FIRST — it gives the exact function names, argument shapes, and return types; this description is the LANGUAGE + how-to (get_library is just the vocabulary).
THE LANGUAGE — plain async JavaScript:
• `bowmark` is a ready global (no import). Call capabilities off it — `await bowmark.<capability>.<method>(...)` — always `await`, they're async.
• Individual sites are callable too, at `await bowmark.providers.<provider>.<fn>(...)`. Use one when you specifically want THAT site; otherwise prefer the capability, which fans out across sites and routes around failures.
• Real control flow: `await`, `if`, loops, array methods (`map`/`filter`/`sort`/`slice`), and `Promise.all` for fan-out.
• `return` a value to get it back (JSON-serialized). `log(...)` for progress lines.
• `bowmark` is the ONLY I/O — no `fetch`, `process`, filesystem, or `import`/`require`. Write a plain async body, not a wrapping function.
• Keep scripts small and deterministic — no infinite loops. Runs in a hard sandbox with CPU + memory + wall-clock limits.
SENDING IT: pass the script text as `run({ script })` — `script` is the only argument (there is no `site` argument; the library exposes every capability under `bowmark`). `result` is whatever you returned; `logs` are your `log()` lines in order; on a throw/timeout `ok:false` and `error` is set.
CHECK `status` BEFORE `ok`. It is `ok` | `error` | `partial` | `needs_user`.
• `partial` means the script RAN and `result` is real and usable, but some of what it called never answered — so the result is narrower than what you asked for. `ok` is still `true`; this is not a failure. `incomplete.summary` says what happened in one sentence, `incomplete.failures` names each call that threw and what the site said, and `incomplete.degraded` names each call that answered while reporting its OWN results thin. You MUST say so when you present the result: name what was missed, and do not describe it as complete, exhaustive, or 'all' of anything. A `partial` you report as whole is a wrong answer, not a slightly smaller right one.
• Before you conclude a `partial` is final, check `incomplete.failures[].fixable`. `fixable: true` means YOUR ARGUMENT was rejected, not the site — the error text names what that function actually takes, so re-read it in `get_library`, fix the argument and run again; that recovers the whole answer. For any other failure re-running usually returns the same thing.
• `needs_user` means a site needs the USER signed in — it is NOT a failure and NOT something you can fix by editing the script. `needs` lists the sites; `meta.handoff.url` is a single-use link that expires (`meta.handoff.expiresAt`). Give the user that URL, say which sites it covers, and WAIT. When they tell you they're done, send the SAME script again unchanged. Do NOT retry before then — it will stop at the same place and cost another run. Do NOT try to log in yourself, ask them for a password, or work around it with a different site.
• Logged-in runs need a Bowmark API key on the connection; if you get `needs_user` saying so, tell the user to add one rather than retrying.
`trace` is the execution trace — every capability you called and the providers it fanned out to under the hood: `[{ kind:'capability', capability:'flights', method:'search', ms }, { kind:'provider', capability:'flights', provider:'google_flights', fn:'search', results, status, ms }, …]`. The script never visits websites — it calls capabilities that route to providers, and the trace is the receipt.
Composition is the point — call a method MULTIPLE times and combine results. To sweep a date range, call the search per date inside `Promise.all` and sort/filter the merged array (each flight result carries its `date`, so you can tell the runs apart). See the `get_library` examples for the exact shape.
SOME capabilities return their rows alongside a `warnings` array — `{ flights, warnings }`, `{ hotels, warnings }`, `{ cars, warnings }`. Others return a bare array. The signature in `get_library` tells you which; go by it rather than assuming. Where there IS a `warnings` array it names any site dropped from the fan-out, and the rows themselves look identical with or without it. Read it, and pass on anything it says rather than quoting a 'cheapest' that only ranks the sites that happened to answer. Dropping `warnings` from what you return does not hide it — the run comes back `status: 'partial'` regardless, because the runtime counts what your script CALLED, not what it chose to report.