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@modelcontextprotocol/server-filesystem

npm / sealed 2026-06-16 / No. d2600fa0

Does @modelcontextprotocol/server-filesystem MCP work in Claude Code and Cursor? Throne executed @modelcontextprotocol/server-filesystem mcp in a single-use Firecracker microVM and replayed both recorded client behaviours. Compatibility verdict: fit. Is @modelcontextprotocol/server-filesystem 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 @modelcontextprotocol/server-filesystem sealed
receiptsealed evidence
scan id
d2600fa0a47c416d93c3e8d5a6df49f5
target
@modelcontextprotocol/server-filesystem
sealed at
2026-06-16 17:49:48Z
evidence hash
sha256:6ed7bb7849c14f8a82f6237311f1cc99301e3683dffd03733ac5a115f4ecddcb
01connectPASS998ms

initialize ok: server secure-filesystem-server 0.2.0, negotiated protocolVersion 2025-11-25, capabilities ['tools']

02discoverPASS10ms

supported: tools/list (14 tools); method not found (tolerated): resources/list, prompts/list

03validate_schemasPASS4ms

all 14 tool inputSchemas are valid JSON Schema

04smoke_test_toolsPASS19ms

called 10 of 10 tools (cap 10, strategy=serial): 1 ok, 9 returned tool-level errors (expected for synthesized args)

05error_handlingPASS5.1s

structured error responses, connection survived, wrong_type_args: read_file:accepted (returned result); read_text_file:accepted (returned result); read_media_file:accepted (returned result); read_multiple_files:accepted (returned result); write_file: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_APPLICABLE1ms

resources capability not declared

08concurrent_callsPASS2ms

ladder 1 overlapping list_allowed_directories calls: max_observed_stable_concurrency=1; all ids answered exactly once at every level

09reconnectPASS915ms

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

01connectPASS1.8s

initialize ok: server secure-filesystem-server 0.2.0, negotiated protocolVersion 2025-11-25, capabilities ['tools'] [request_strategy=pipelined, connection_count=2, second connection established]

02discoverPASS18ms

supported: tools/list (14 tools); method not found (tolerated): resources/list, prompts/list; notes: connection 2 confirms 14 tools

03validate_schemasPASS4ms

all 14 tool inputSchemas are valid JSON Schema

04smoke_test_toolsPASS14ms

called 10 of 10 tools (cap 10, strategy=pipelined): 1 ok, 9 returned tool-level errors (expected for synthesized args)

05error_handlingPASS5.0s

structured error responses, connection survived, wrong_type_args: read_file:accepted (returned result); read_text_file:accepted (returned result); read_media_file:accepted (returned result); read_multiple_files:accepted (returned result); write_file: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_APPLICABLE1ms

resources capability not declared

08concurrent_callsPASS10ms

ladder 1/2/4/6 overlapping list_allowed_directories calls: max_observed_stable_concurrency=6; all ids answered exactly once at every level

09reconnectPASS1.7s

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-INSTALL-03 / Install-time script execution (npm lifecycle)

"prepare" runs on git-dependency installs and local dev (not registry installs): 'npm run build'

package/package.json
VERDICT: FIT14 of 18 steps exercised across 2 clientsSANDBOXED RUN, submitted server executed in a disposable microVM, compatibility: 0 fail / 0 warn (14 of 18 steps exercised across 2 clients) / security: review, 1 finding(s), 0 highsealed by THRONE / No. d2600fa0 / 2026-06-16
scopeattestation tuple
target
@modelcontextprotocol/server-filesystem 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 17:49:48Z
evidence hash
sha256:6ed7bb7849c14f8a82f6237311f1cc99301e3683dffd03733ac5a115f4ecddcb
valid until
2026-09-14
THRONE: FITwear the crown

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[![THRONE: FIT](https://api.usethrone.dev/api/badge/%40modelcontextprotocol%2Fserver-filesystem)](https://usethrone.dev/server/modelcontextprotocol-server-filesystem)
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