Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
git clone --depth 1 https://github.com/HasData/google-flights-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/hasdata/google-flights-mcp/hasdata-google-flights)<a href="https://agentmods.dev/rules/hasdata/google-flights-mcp/hasdata-google-flights"><img src="https://agentmods.dev/badge/rules/hasdata/google-flights-mcp/hasdata-google-flights/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/rules/hasdata/google-flights-mcp/hasdata-google-flights"><img src="https://agentmods.dev/badge/rules/hasdata/google-flights-mcp/hasdata-google-flights.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00017 | $0.00582 |
| Opus 5.5 | $0.00007 | $0.00233 |
| Sonnet 5.5 | $0.00003 | $0.00116 |
| Haiku 4.5 | $0.00002 | $0.00058 |
Grade A, and why
hasdata-google-flights scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 37 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Google Flights through HasData
One tool, hasdata_google_travel_flights_getGoogleFlights. It needs departureId, arrivalId and outboundDate, and it returns the itineraries Google shows for that route and day.
Airports are IATA codes such as JFK or location kgmids, never city names. A city name comes back as a 400 with requestMetadata.status set to error. Several airports can share one field, comma-separated.
Two rules the validator enforces
type defaults to roundTrip, and a round trip without returnDate fails validation before it becomes a search. includeAirlines and excludeAirlines are one or the other, and sending both is rejected the same way.
Validation failures arrive as tool output with isError set to true, carrying a 422 and naming the offending field and the rule it broke, such as requiredWhen or mutuallyExclusive. The call itself succeeds, so nothing in the transport reports the problem.
Reading the payload
Itineraries split into bestFlights and otherFlights. A route with nothing flying that day returns both arrays empty and a status of ok, so test for itineraries before ranking them.
totalDuration is minutes. carbonEmissions.thisFlight is grams, so 433000 is 433 kg, and differencePercent compares it to typicalForThisRoute where a negative number means cleaner than average.
priceInsights sits beside the itineraries with lowestPrice, a typicalPriceRange, a priceLevel and a priceHistory of timestamp and price pairs. That is where the answer to "is this a good fare" lives, rather than in the fare itself.
Tokens
departureToken picks an outbound option and fetches its return leg, bookingToken fetches booking options for a chosen itinerary. Both come from a previous response, and each is another billed call, so a round trip priced end to end is at least two.
Fares move constantly. Quote the date you pulled them alongside the number.
Prompts and resources
The server also serves resources that spell out the accepted values of every parameter that takes a fixed list, each one at hasdata://google_travel_flights/<parameter>. Reading one spends no credits and makes no upstream request, which beats discovering the vocabulary from a rejected call. Listing them needs no API key either, so a client can read them before the user has connected an account.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago Changed · +6 lines f9abae2a063c
- 23d ago First seen · 31 lines · 17 tokens per session scan A 42c9201173d7
hasdata-google-flights is a cursor rule published in the GitHub repository HasData/google-flights-mcp (6 stars, last pushed 4d ago), licensed MIT. It adds 17 tokens to every session and 582 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-23.
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