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@browserbasehq/mcp

npm / sealed 2026-06-16 / No. d3d2b3a3

Does @browserbasehq/mcp MCP work in Claude Code and Cursor? Throne executed @browserbasehq/mcp mcp in a single-use Firecracker microVM and replayed both recorded client behaviours. Compatibility verdict: fit. Is @browserbasehq/mcp mcp safe? Static security scan: 1 finding(s) to review under security ruleset v1. The full per-step results, security findings, scan date, and evidence hash are below.

> throne registry @browserbasehq/mcp sealed
receiptsealed evidence
scan id
d3d2b3a32d414dae96957abcbb8c2cbf
target
@browserbasehq/mcp
sealed at
2026-06-16 17:22:49Z
evidence hash
sha256:fb8629c0e6cc6db7c76b6e935af87c799d3fcda18f4ab29f6c0e4716ffac770b
01connectPASS1.4s

initialize ok: server Browserbase MCP Server 3.0.0, negotiated protocolVersion 2025-11-25, capabilities ['resources', 'tools']

02discoverPASS9ms

supported: tools/list (6 tools), resources/list (0); method not found (tolerated): prompts/list

03validate_schemasPASS3ms

all 6 tool inputSchemas are valid JSON Schema

04smoke_test_toolsPASS1.8s

called 6 of 6 tools (cap 10, strategy=serial): 1 ok, 5 returned tool-level errors (expected for synthesized args)

05error_handlingPASS7.3s

structured error responses, connection survived, wrong_type_args: start:accepted (returned result); end:accepted (returned result); navigate:accepted (returned result); act:accepted (returned result); observe:accepted (returned result); unknown_method: error(-32601); invalid_id: no response (silent), connection alive; oversized_input: accepted (returned result); recovery: accepted (returned result); cancellation: accepted (returned result); old_version: accepted old version 2024-10-07, negotiated 2024-10-07, server may have stale protocol handling

06streamingNOT_APPLICABLE1ms

no streaming-capable tool declared by this server

07resource_lifecycleNOT_APPLICABLE8ms

server declares resources but lists none

08concurrent_callsWARN686ms

ladder 1 overlapping start calls: max_observed_stable_concurrency=1; all ids answered exactly once, but every call returned an error (tool-level isError result), the tool may need runtime dependencies this sandbox does not provide

09reconnectPASS1.5s

transport closed and relaunched; re-handshake ok (protocolVersion 2025-11-25, first session was 2025-11-25)

01connectPASS2.9s

initialize ok: server Browserbase MCP Server 3.0.0, negotiated protocolVersion 2025-11-25, capabilities ['resources', 'tools'] [request_strategy=pipelined, connection_count=2, second connection established]

02discoverPASS22ms

supported: tools/list (6 tools), resources/list (0); method not found (tolerated): prompts/list; notes: connection 2 confirms 6 tools

03validate_schemasPASS7ms

all 6 tool inputSchemas are valid JSON Schema

04smoke_test_toolsPASS876ms

called 6 of 6 tools (cap 10, strategy=pipelined): 1 ok, 5 returned tool-level errors (expected for synthesized args)

05error_handlingPASS7.5s

structured error responses, connection survived, wrong_type_args: start:accepted (returned result); end:accepted (returned result); navigate:accepted (returned result); act:accepted (returned result); observe:accepted (returned result); unknown_method: error(-32601); invalid_id: no response (silent), connection alive; oversized_input: accepted (returned result); recovery: accepted (returned result); cancellation: accepted (returned result); old_version: accepted old version 2024-10-07, negotiated 2024-10-07, server may have stale protocol handling

06streamingNOT_APPLICABLE0ms

no streaming-capable tool declared by this server

07resource_lifecycleNOT_APPLICABLE2ms

server declares resources but lists none

08concurrent_callsWARN1.3s

ladder 1/2/4/6 overlapping start calls: max_observed_stable_concurrency=6; all ids answered exactly once, but every call returned an error (tool-level isError result), the tool may need runtime dependencies this sandbox does not provide

09reconnectPASS2.9s

transport closed and relaunched; re-handshake ok (protocolVersion 2025-11-25, first session was 2025-11-25)

chatgpt desktop calibratingemulation profile pending real-traffic captureCOMING SOON
SECURITY: REVIEW / 1 finding(s) / review recommended
LOWTHR-NET-05 / Hardcoded outbound endpoints

2 non-local endpoint host(s) referenced in code, verify each is expected for this server's purpose: docs.browserbase.com (package/config.d.ts:14), www.browserbase.com (package/dist/sessionManager.js:141)

package/config.d.ts:14
VERDICT: FIT14 of 18 steps exercised across 2 clientsSANDBOXED RUN, submitted server executed in a disposable microVM, compatibility: 0 fail / 2 warn (14 of 18 steps exercised across 2 clients) / security: review, 1 finding(s), 0 highsealed by THRONE / No. d3d2b3a3 / 2026-06-16
scopeattestation tuple
target
@browserbasehq/mcp npm
engine
sandboxed
claude code
calibration: partial recorded=9,spec=0,assumed=9
cursor
calibration: partial recorded=11,spec=0,assumed=7
chatgpt desktop
calibration: unavailable recorded=0,spec=2,assumed=16
steps exercised
14 of 18
test suite
v1.0.0
security ruleset
v1.0.0
sealed at
2026-06-16 17:22:49Z
evidence hash
sha256:fb8629c0e6cc6db7c76b6e935af87c799d3fcda18f4ab29f6c0e4716ffac770b
valid until
2026-09-14
THRONE: FITwear the crown

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[![THRONE: FIT](https://api.usethrone.dev/api/badge/%40browserbasehq%2Fmcp)](https://usethrone.dev/server/browserbasehq-mcp)
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