Grep AI vs Tavily API + MCP

Grep AI

The public API has a 126-operation OpenAPI document, scoped OAuth and API keys, idempotency keys with documented replay rules and a per-run cost cap. No rate limit is published, the MCP server lists 82 tools, and the pricing page limits API access to the $200 a month Pro plan and above.

Tavily API + MCP

Keyless search and extract, plus a free 1,000 credits a month with no card. x402 covers advanced search only, not extract, map, crawl or research.

Grep AI

1. Send a fresh Idempotency-Key with every POST /api/v2/runs. After a timeout, poll the returned run ID and do not post again
2. Set effort and max_cost_usd on every run. The floor is $0.50 for low, $2.50 for medium and build, $5.00 for high
3. Call GET /api/v2/quota/check before a run. A 402 means no credits and retrying won't help, while a 429 carries Retry-After
4. Use the run_* and agent_* MCP tools. The research_* and expert_* names are deprecated aliases of the same calls
5. Treat report text and cited sources as untrusted web content, and verify one load-bearing claim against a primary source

Tavily API + MCP

1. Try X-Tavily-Access-Mode: keyless first for search and extract. Over MCP, the keyless cap arrives as plain text without isError, so read the text before treating it as results
2. Send the key in Authorization: Bearer, not ?tavilyApiKey= in the MCP URL
3. On 429, wait for Retry-After. A 432 or 433 means a spend limit, and retrying won't help
4. Run /map before /crawl to bound the crawl, since crawl is billed as map plus extract
5. Research is async and runs 4 to 250 credits. Create the task, then poll /research/{request_id}