Loading ToolBench

Reading the current corpus…

privatebin-mcp MCP server · C · ToolBench

← Browse

privatebin-mcp

github.com/aaronsteers/privatebin-mcp

MCP server for secure encrypted sharing via PrivateBin

<=2025-11-25STDIO3 tools

62/100

Definition Quality84

Protocol Readiness45

Supportability36

Spec posture

Inferred effective spec <=2025-11-25·current baseline 2026-07-28

Static source inference · medium confidence · detected: Logging

Deprecated protocol patterns detected

Summary

Three well-named tools with clear action verbs (create_, save_). Tool descriptions are comprehensive (180-220 chars) and explain WHAT happens, WHEN to use, and security implications. Input schemas are present with proper JSON Schema types, enums, patterns, and field descriptions. However, output schemas lack explicit documentation, return types are inferred from code (string URLs, implicit file write). Security-focused design (environment-injected credentials, no data exfiltration) is excellent but not reflected in schema annotations. Tool composition is clean (three separate concerns: create from string, create from file, decrypt to file). Missing: tool annotations (readOnlyHint, destructiveHint, idempotentHint), explicit output schema documentation, and error-recovery guidance in descriptions.

Tools (3)

create_encrypted_share_from_filewritesource verified85/100

Create and post an encrypted paste from file contents. This tool reads a file, encrypts its contents locally, and posts it to PrivateBin. The server URL is configured via PRIVATEBIN_SERVER_URL environment variable.

create_encrypted_share_from_stringwritesource verified85/100

Create and post an encrypted paste from string content. This tool encrypts content locally and posts it to PrivateBin. The server URL is configured via PRIVATEBIN_SERVER_URL environment variable and cannot be overridden by the agent (security feature to prevent data exfiltration).

save_decrypted_share_to_filewritesource verified82/100

Retrieve and decrypt a PrivateBin share, saving it to a file. This tool retrieves an encrypted paste from PrivateBin, decrypts it locally, and saves the content to a file. The decrypted content is NOT returned to the agent - it's only written to the file (security feature to keep sensitive data hidden from LLMs).

Issues (4)

HIGHresponse-shaper ↗

Output schemas are not explicitly documented. The code shows tools return `str` (URLs) or implicit file writes, but LLMs cannot see the structure. Return type documentation is required so agents know what to expect.

create_encrypted_share_from_stringcreate_encrypted_share_from_filesave_decrypted_share_to_file

HIGHtool-annotation ↗

Missing tool annotations. Tools that modify state (create_* are WRITE; save_* is WRITE) should declare destructiveHint=true or idempotentHint where applicable. Burn-after-reading pastes are non-idempotent. Annotations guide agent planning.

create_encrypted_share_from_stringcreate_encrypted_share_from_filesave_decrypted_share_to_file

MEDIUMrecovery-guide ↗

Error handling lacks recovery guidance. RuntimeError and generic exceptions are raised but do not explain what the agent should do next (e.g., 'Check PRIVATEBIN_SERVER_URL is set and reachable').

create_encrypted_share_from_stringcreate_encrypted_share_from_filesave_decrypted_share_to_file

Recommendations

Document explicit output schemas. For create_* tools: 'Returns a string containing the full PrivateBin URL with encryption key in the URL fragment (e.g., https://example.com/abcd1234#key456). The fragment contains the decryption key and must be preserved.' For save_* tool: 'Writes decrypted content to output_path and returns a success message; does NOT return the decrypted content (security feature).'
Add tool annotations in the FastMCP decorator: `@app.tool(name='create_encrypted_share_from_string', annotations={'io.modelcontextprotocol/destructiveHint': {'destructive': True}})` to signal this modifies remote state.
Improve error messages with actionable recovery steps. Example: `raise RuntimeError(f'Failed to connect to PrivateBin at {server_url}. Check that PRIVATEBIN_SERVER_URL is set correctly and the server is reachable.') from e`
Clarify passcode parameter: 'Optional passcode for additional protection. If omitted, falls back to PRIVATEBIN_DEFAULT_PASSCODE environment variable (may be empty for no passcode). If provided, overrides the default.'
Add a confirmation/dry-run pattern for destructive operations. Consider a tool like `preview_encrypted_share_options()` that shows what settings would be used before creation, enabling agents to verify before irreversible operations.

Spec posture evidence

Inferred effective spec: <=2025-11-25.

Relies on Logging (deprecated) - log to stderr or use OpenTelemetry

Score history

Overall score trend

↑ 3 points across a rubric change (v1 → v2)

62/100

Scored	Grade	Overall	Spec posture	Rubric
2026-09-22	C	62	<=2025-11-25	v2
2026-03-09	D	59	-	v1