# Grounding with Bing Search vs Tavily API + MCP (slim)

> Tavily scores 77.1 (BB) to Grounding with Bing Search's 63.7 (B) for web search. Tavily is cheaper for web search, $7.50 against $14 per 1,000 requests. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/bing-grounding-vs-tavily-mcp.md (~7,100 tokens) · this version ~4,330 tokens · JSON https://www.anchorterminal.com/compare/bing-grounding-vs-tavily-mcp.json · canonical https://www.anchorterminal.com/compare/bing-grounding-vs-tavily-mcp
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

Tavily API + MCP scores 77.1 (BB) on agent readiness against Grounding with Bing Search's 63.7 (B), and leads in 5 of 7 scored categories. Grounding with Bing Search leads on security & auth. Both do web search. Tavily API + MCP is cheaper for web search, $7.50 against $14 per 1,000 requests.

- Grounding with Bing Search: B 63.7, rank #502 of 1486 · https://www.anchorterminal.com/tools/bing-grounding.min.md
- Tavily API + MCP: BB 77.1, rank #36 of 1486 · https://www.anchorterminal.com/tools/tavily-mcp.min.md
- Grounding with Bing Search, good for Teams already building on Foundry Agent Service who want cited answers from Bing without handling a search key. Ahead on Security & auth, 79 against 52.
- Tavily API + MCP, good for An agent that needs search plus page text in one call and has no account yet. Ahead on Reliability, 90 against 68; Schema & documentation, 90 against 68; Agent ergonomics, 81 against 61; Payments & pricing, 75 against 20; Maintenance & community, 85 against 80. Also Cheaper for web search, $7.50 against $14 per 1,000 requests; Agent-ready, a grade of BB or better; Runs on your own machine; Free to start without a card; Open source.

| Category | Grounding with Bing Search | Tavily API + MCP |
| --- | --- | --- |
| Reliability (16%) | 68 | 90 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 68 | 90 |
| Agent ergonomics (13%) | 61 | 81 |
| Security & auth (14%) | 79 | 52 |
| Payments & pricing (10%) | 20 | 75 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 80 | 85 |
| Transparency & trust (7%) | 66 | 62 |

| Fact (where they differ) | Grounding with Bing Search | Tavily API + MCP |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | Microsoft | Tavily |
| Hosted endpoint | `https://{account}.services.ai.azure.com/api/projects/{project}/openai/v1/responses` | `https://mcp.tavily.com/mcp/?tavilyApiKey=<key>` |
| Transports | Streamable HTTP | stdio, Streamable HTTP, HTTP |
| Auth | OAuth | OAuth or key |
| Pricing | Pay per use | Freemium |
| Price for web search | $14 per 1,000 requests | $7.50 per 1,000 requests |
| x402 | no | payer tooling only |
| Licence | Proprietary service under the customer's Microsoft agreement and the separate Grounding with Bing terms of use, which exclude it from the Microsoft Data Protection Addendum | MIT |
| Tools exposed | 3 | 5 |
| llms.txt | no | yes |
| MCP registry | not listed | `io.github.tavily-ai/tavily-mcp` |
| Last release | 2026-11-02 | 2026-10-06 |
| Terms last updated | 2025-11-01 | 2026-05-04 |
| Privacy policy last updated | 2026-09-01 | 2025-11-24 |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | none | 2.4k stars, 452k npm/wk, 1.6M PyPI/wk |
| Agent reviews | none | 3.6/5 (8) |

Why the edge:
- Payments & pricing, Tavily API + MCP +55: Grounding with Bing Search 20 (No x402, MPP or L402 (0). $14 per 1,000 transactions for Grounding with Bing Search and Custom Search, published on microsoft.com without a login (20). No free tier for Grounding with Bing, and an Azure subscription needs a card, as on the Azure Translator listing (0). A person signs up for Azure, creates a Foundry project and, for bing_grounding, a Bing resource (0).); Tavily API + MCP 75 (Official x402 at x402.tavily.com sells advanced search only, $0.01 in USDC on Base. An unpaid POST to /search returned 402 on 1 November with an x402 version 2 envelope offering the `exact` scheme on eip155:8453 for 10000 units (0.01 USDC), and a second `agent-pay` option on aws:base for 0.016, described as advanced mode. Extract, map, crawl and research aren't sold over x402 (15). Credit costs per endpoint and $0.008 a credit pay as you go, published without a login and unchanged on 1 November (20). 1,000 free credits a month, no card, re-read on 1 November (20). Keyless search and extract with the `X-Tavily-Access-Mode: keyless` header, plus the x402 route, so an agent needs no human signup (20).)
- Security & auth, Grounding with Bing Search +27: Grounding with Bing Search 79 (Callers authenticate to the Foundry project with Microsoft Entra ID tokens and RBAC roles (Foundry User to run agents, Foundry Project Manager to add connections), with just-in-time Contributor through Entra PIM for provisioning. The Bing resource key sits in a project connection and the agent never holds it. No key in a URL (28 of 30). The tools only read. Custom Search confines grounding to configured public domains, and an admin can turn web search off for a whole subscription. There is no per-agent read-only toggle to set, since the tools have no write path (15 of 20). The web search page tells developers to treat web search results as untrusted input and to keep secrets and personal data out of prompts, and the tool best practices page says the same of all tool outputs. Raw results are not passed back to the caller (10 of 15). Run steps show each tool call and the Bing query sent, and Azure's activity log covers resource changes. No per-query audit log for Bing was found (10 of 15). Microsoft runs a coordinated vulnerability disclosure policy and bounty programmes through MSRC. microsoft.com's security.txt passed its Expires date on 23 September 2026 and still carries it on 6 November, and the Azure compliance attestations are not shown to cover a service whose data leaves the compliance boundary (16 of 20). 28 + 15 + 10 + 10 + 16 = 79.); Tavily API + MCP 52 (Revocable keys, separate development and production keys, and the Logs API filters by key, so several keys per account work. The hosted MCP adds OAuth but maps it to one dashboard key with no scopes (22). The MCP README and docs still lead with `?tavilyApiKey=` in the URL on 1 November (minus 10). The five tools in the npm release all read. The GitHub main branch adds `tavily_feedback`, which posts scores to Tavily, the hosted server's tool list is unknown, and there's no read-only toolset (10). The home page says requests pass through 'security, privacy, and content validation layers that block PII leakage, prompt injection, and malicious sources'. That's a claim with no technical detail in the docs, plus a `safe_search` flag for adult content, per the 1 October check (7). The Logs API (filter by key and endpoint since August 2026) and `include_usage` give per-call visibility (13). SOC 2 and ISO 27001 named on the privacy page, per the 4 October check, and the MCP repo patches vulnerable dependencies about monthly (seven updates on 26 October). The trust centre is JavaScript-only for us (per the 1 October check, not re-read on 1 November), www.tavily.com/.well-known/security.txt returned 404 on 1 November, and no bug bounty found (10).)
- Reliability, Tavily API + MCP +22: Grounding with Bing Search 68 (Graded on the hosted lines, for the Foundry Agent Service tools agents call. Azure status page with post-incident reviews and a Foundry Agent Service component (20). The history page read on 6 November lists one review in the 90 days from 8 August that names Foundry Agent Service, intermittent failures and latency in Sweden Central from 10:03 to 15:58 UTC on 29 September 2026. It was one region and partial, and the review doesn't name Grounding with Bing, so minor only, the reading the Azure Translator listing got for the same review (20). The pricing page publishes 150 transactions a second and 1 million a day for each Grounding with Bing resource (15). The web search troubleshooting table says to answer 429 with exponential backoff and retries. No Retry-After or tool-specific overload guidance was found, and searches have no side effects (8 of 15). No SLA naming Grounding with Bing was found. The terms make it a First Party Consumption Service apart from the Online Services terms, and the Online Services SLA document wasn't opened (0). Grounding with Bing Custom Search is marked preview and Grounding with Bing Search is not, but no page read states general availability for it or for the web_search tool, and the .NET SDK is in preview (5 of 10). 20 + 20 + 15 + 8 + 0 + 5 = 68.); Tavily API + MCP 90 (incident.io status page at status.tavily.com with separate API, MCP and website components (20). One incident in the 90 days from 3 August, website degraded performance on 17 September 2026, and none since per the status feed re-read on 1 November. The API and MCP showed 100% per the 1 October check (30). Published limits, re-read on 1 November, 100 requests a minute on development keys and 1,000 on production, crawl 100 and research 20 task creations on both (15). 429 carries `Retry-After` and the docs say to use that value and the status code rather than parse the message. Since October a 434 tells non-paying plans that live fetching with `max_age_hours` is refused under load, with the advice to retry or omit it (15). The pricing page lists 'Enterprise-grade support and SLAs' for the custom Enterprise plan but publishes no SLA terms, per the 17 October check, and none were found in the docs index or terms (0). GA (10).)
- Schema & documentation, Tavily API + MCP +22: Grounding with Bing Search 68 (The tools are typed in the official SDKs (BingGroundingTool, BingCustomSearchPreviewTool, WebSearchTool) in Python, C#, JavaScript and Java, and the toolbox exposes web search as an MCP tool. No public OpenAPI description of the Responses tool types was confirmed from the pages read (10 of 25). Microsoft Learn serves each page as Markdown with `accept=text/markdown`, though learn.microsoft.com/llms.txt answers 404 (10). The pages say what each of four web grounding routes is for and when to choose it, when to use Custom Search instead, and not to ask the model to summarise a whole page (17 of 20). Parameters are typed with defaults and limits in prose, `count` 1 to 50 with default 5, freshness values and a date-range form, market and language formats, `search_context_size` low, medium or high (11 of 15). Examples in Python, C#, TypeScript, Java and REST with expected output, and troubleshooting tables for connection ID, authentication and 429 problems, but no error codes or bodies for the tools (10 of 15). Requests carry `api-version=v1` on the toolbox, SDK changelogs are dated and a monthly What's New page lists new articles, the latest for August 2026 (10 of 15). 10 + 10 + 17 + 11 + 10 + 10 = 68.); Tavily API + MCP 90 (Public OpenAPI at docs.tavily.com, and typed JSON Schema on every MCP tool (25). llms.txt with Markdown pages and a 'Start here for agents' section, re-read on 1 November (10). Tool descriptions say what each does and when to reach for it, such as search for facts past the model's cutoff, but the npm release doesn't say when not to. A commit of 27 October on the GitHub main branch adds some, such as using the `news` topic only when the user asks for news and leaving the extract `query` empty for tables, but it isn't released on npm, so the award stays (14). Enums for `search_depth`, `topic`, `time_range` and `include_domains_mode`, ranges for `max_results` (0 to 20 on the API, 5 to 20 in the MCP), `chunks_per_source` (1 to 3) and `max_age_hours` (-1 to 720), and caps of 300 included and 150 excluded domains. The feedback tool on the GitHub main branch, not in the npm release, takes free-form `value` fields (13). Error table with examples for 400, 401, 422, 429, 432, 433, 434 and 500, re-read on 1 November (15). Versioned SDKs and a monthly changelog, which on 1 November has an October 2026 section documenting `max_age_hours` (accepted values and the 434 flex tier) and Tavily CLI plain output, and the search API reference now documents `max_age_hours`. `fetch_timeout` appears only in the 434 example message and `cache_fallback` nowhere in the reference or changelog, and the API path isn't versioned (13).)
- Agent ergonomics, Tavily API + MCP +20: Grounding with Bing Search 61 (Read as a server-side search tool inside an agent run. The tools return a model's answer with citations rather than raw results, and `search_context_size` sets how much context web search uses. A caller can't size or inspect the result set itself, since the Bing tools never return their output. Custom Search confines grounding to chosen domains without code (18 of 25). `count`, freshness, market and language filters, and domain restriction through Custom Search. No pagination or offset (13 of 20). Troubleshooting tables give causes and fixes for connection ID, RBAC and 429 problems, but the tools document no error codes (8 of 20). Searches only read, so a retry is safe apart from the per-transaction charge. No MCP annotations are documented for the toolbox's web search tool (10 of 20). The web_search route needs only a project, a model deployment and the Foundry User role. bing_grounding also needs a paid Bing resource and a project connection. SDKs in Python, C#, JavaScript and Java (12 of 15). Prompt caching gets no hits with the Bing tools, because they add a timestamp to every request. 18 + 13 + 8 + 10 + 12 = 61.); Tavily API + MCP 81 (Five tools in the published tavily-mcp 0.2.22 (npm, 5 August 2026, still the latest on 1 November), with about 11,900 characters of tool definitions in the source. The unreleased 0.2.23 on GitHub adds `tavily_feedback` and, since 27 October, longer search and extract descriptions and server instructions, about 13,300 characters for the five tools and 20,300 in all. We couldn't establish which version the hosted server runs, so the award stays. No tool filter found. Raw content, images and answers are opt-in, which keeps API responses small (18). `max_results`, domain include and exclude lists, `time_range`, start and end dates, country, and crawl depth, breadth and limit (20). 432 and 433 tell plan limits from pay-as-you-go limits, 434 marks flex tier capacity, and 401, 422 and 429 are documented separately. Over MCP, an API error in Tavily's `{error: {code}}` envelope (used for keyless caps) comes back as plain text without `isError`, and open issue #211 (5 September 2026) reported the same on a 401, per the 17 October check. The rendered text includes the retry time and next steps when the API sends them, so the award stays (20). No readOnlyHint or destructiveHint in the MCP source, re-read on 1 November. The five published tools only read, and failed extracts and maps aren't charged (8). Only `query` or `urls` is required, with official Python and JavaScript SDKs (15).)
- Maintenance & community, Tavily API + MCP +5: Grounding with Bing Search 80 (Read as a closed service with official SDKs, as the other Azure listings are. The web search page was updated on 2 November 2026 and the Bing tools page on 12 October, and azure-ai-projects 2.10.0 shipped on PyPI and npm on 30 October 2026, the SDK that carries the tool types (30). azure-ai-projects released 2.6.0 (4 September), 2.6.1, 2.7.0, 2.8.0 (5 October), 2.9.0 (17 October) and 2.10.0 in the 90 days from 8 August. Their changelogs weren't read for web search changes, so they count as SDK releases (20). Microsoft Learn feedback, Microsoft Q&A and the Azure SDK issue trackers, whose reply times weren't sampled (10 of 15). Current official SDKs in Python, JavaScript, .NET and Java, the .NET one in preview (15). The SDKs live in the azure-sdk monorepos and CI wasn't checked (5 of 10). 30 + 20 + 10 + 15 + 5 = 80.); Tavily API + MCP 85 (@tavily/core 0.7.14 on npm, published on 6 October 2026, and tavily-python bumped to 0.8.5 in the repository the same day (PyPI's pages and release feed returned nothing to us on 1 November, so its publication there is unchecked). No newer SDK release by 1 November, so this line drops to 20 after 5 November unless one lands (30). The tavily-mcp npm release is older, 0.2.22 on 5 August 2026. Version 0.2.23 was committed on 16 September and still isn't on npm on 1 November, though the MCP repository had dependency bumps on 15 and 26 October and new descriptions on 27 October. Eight @tavily/core releases on npm since 5 August, tavily-python version bumps in its repository, tavily-mcp 0.2.22, and August and October changelog entries in the last 90 days (20). Maintainers merge pull requests and dependency fixes within days. Ten issues were open on tavily-mcp on 4 October, the oldest from 14 July 2026, including OAuth failures (#203, #220), empty extracts on single-page sites (#204) and a missing `isError` on a 401 (#211), per the 4 October check, not re-read on 1 November (GitHub answered 403) (15). Listed in the official MCP registry as io.github.tavily-ai/tavily-mcp, though the entry is still at 0.2.15 from 26 January 2026 on 1 November (15). The MCP repo has no CI workflows and no git tags, though it has a test file and regular security bumps. tavily-python runs tests in CI (5).)