Grounding with Bing Search vs Brave Search API + MCP

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.

Brave Search API + MCP 58

Plain API keys in the X-Subscription-Token header. Several keys per account, revocable from the dashboard, with rotation advice, but no scopes (20). Read-only by nature, with tool allow and deny lists in the MCP server. The HTTP transport binds to 127.0.0.1 and checks Origin (18). Results are untrusted web text and LLM Context returns page content, and we found no prompt-injection guidance in the API docs or the MCP README (0). No per-call audit log found. Rate-limit headers show quota use only (0). SOC 2 Type II attestation, a HackerOne bounty, a pen test in April 2025 and a security.txt at brave.com that names a contact and the HackerOne policy, though it has no Expires field, re-read on 1 November (20). 20+18+0+0+20 = 58.

Grounding with Bing Search 66

Closed service. The terms of use, updated November 2025, are separate from the Online Services terms and sit under the customer's Microsoft agreement (15 of 30). The docs and the terms agree that the Data Protection Addendum and the Product Terms' privacy and security terms don't apply, that Microsoft and the customer are independent controllers, and that the query and parameters leave the Azure compliance and geographic boundary. The terms defer storage and use of query data to the general Microsoft Privacy Statement and state no retention period (15 of 30). The Bing Search APIs retirement was announced on 16 May 2025 for 11 August 2025, under three months' notice, and the web search page marks the Deep Research tool deprecated with a replacement. Microsoft's lifecycle policy covers Azure services, but no deprecation terms for Grounding with Bing were found (10 of 20). Data location for Bing processing isn't stated, and no sub-processor list for it was found (5 of 20). 15 + 15 + 10 + 5 = 45.

Brave Search API + MCP 81

The MCP server is MIT. The API is closed with published terms, so between the two bands (20). Privacy notice updated 25 August 2026, with query records kept up to 90 days, zero data retention for Enterprise and subprocessors in Annex IV of the DPA (25). Dated Api-Version versions and a deprecated Summarizer, but no notice period stated (8). Brave Software Inc. in the US is named, and subprocessors sit in the DPA annex. We found no data-location statement (10). 20+25+8+10 = 63.

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.

Brave Search API + MCP 80

status.brave.app (Better Stack) lists a Brave Search API component monitoring api.search.brave.com, showing 100% uptime with every two-day mark from 6 May to 1 November 2026 operational, and a Search API Dashboard monitor at 99.996%. The 1 October note read the page as unmonitored, but its marks go back to May (20). No incident in the 90 days from 3 August on the page or its feed, and the docs' own status log still ends on 27 March 2025, so a clean record on a readable page (20). Rate limits published per plan, 50 QPS Search, 2 QPS Answers, 100 QPS Spellcheck and Autosuggest, in a 1-second sliding window, per the 1 October check (15). 429 on overrun, X-RateLimit-Reset in seconds and exponential backoff guidance. Searches are reads, so no idempotency keys are needed (15). No SLA on any self-serve plan (0). GA (10). 20+20+15+15+0+10 = 80.

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.

Brave Search API + MCP 72

Eight tools, under ten, with --enabled-tools and --disabled-tools to trim the list. Country and language enums make the web search schema long (22). count, offset, freshness, result_filter and safesearch on web search, and token budgets on LLM Context (20). 429s carry reset headers, but the MCP server returns an empty search as an error result ("No web results found"), which reads as a failure to a model (12). Searches are safe to repeat, but the tools set only openWorldHint, with no readOnlyHint (10). Only query is required. No official SDK in any language (8). 22+20+12+10+8 = 72.