Grounding with Bing Search vs Serper

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.

Serper 3

No changelog, release notes, SDK or package found, so no dated release or API change to count (0, 0). No public changelog. Support is by email per the privacy policy (3). No official SDKs (0). No packages or CI to assess (0).

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.

Serper 6

No OpenAPI or other spec (0). serper.dev/llms.txt returns 404 and there are no Markdown docs (0). The documentation is the playground, a JavaScript page that showed us no text. Per the 30 September check it lists the verticals and parameters such as gl and hl, so a few points for descriptions (3) and typed inputs (3). No examples or error responses we could read (0). No changelog or API versioning (0).

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.

Serper 20

API key in the X-API-KEY header, never in the URL. No scopes, multiple keys or rotation found (10). Read-only search with no write surface, but no MCP annotations or least-privilege mode (10). Returns third-party titles and snippets with no prompt-injection guidance (0). No per-call log or audit trail found outside the logged-in dashboard, which we couldn't see (0). serper.dev/.well-known/security.txt returns 404, and we found no disclosure policy, bug bounty or certification (0).

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.

Serper 30

No status page. status.serper.dev answers with a 302 to Atlassian's Statuspage marketing site (0). No readable incident history (5). Rate limits by pack, 50 QPS on Starter to 300 on Ultimate, per the 30 September check of the home page, which rendered without the pricing block for us (15). No 429 or retry guidance found (0). No SLA in the terms (0). GA (10).

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.

Serper 32

Closed service. The terms exist (last updated 29 May 2024, UK law) but name no legal entity, only 'Serper' (8). The privacy policy (5 November 2025) says the service 'should normally not lead to the processing of personal data' and keeps account data for the life of the account, but states no retention period for queries or results (10). No deprecation policy or dated notices (0). Subprocessors are described by category (payments, email, hosting) without names, with transfers outside the EEA under Standard Contractual Clauses (5).

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.

Serper 35

Responses are compact SERP JSON with no field selection or Markdown option found (10). Country and language parameters per the 30 September check, and ten separate verticals. We couldn't confirm pagination or result-count parameters from the docs (8). No documented error responses (0). Searches are read-only and only successful queries use credits, per the 30 September check of the home page (10). One required field (q) and no official SDK (7).