# list_available_extensions A read tool on the Mcpg MCP server. Agent View of the PolicyLayer registry record for `list_available_extensions`. HTML page: https://policylayer.com/tools/io-github-devopam-mcpg/list-available-extensions ## Facts - Tool: `list_available_extensions` - Server: Mcpg (`pypi:mcpg`) — https://policylayer.com/tools/io-github-devopam-mcpg.md - Install: `npx -y pypi:mcpg` - Homepage: https://github.com/devopam/MCPg - Risk category: Read (Low risk) - Registry record: grade F, identity unverified - Server rate-limited: no - Parameters: 0 - Recommended policy verdict: Allowed ## Example call (MCP tools/call, JSON-RPC 2.0) ```json { "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "list_available_extensions", "arguments": {} } } ``` ## Why list_available_extensions is rated Low This is a passive information retrieval tool that queries what extensions are available in the PostgreSQL server. It performs no writes, deletions, or external operations. The tool name follows the 'list' pattern typical of Read operations. Low severity because even if misused, it only exposes metadata about available extensions, which is generally non-sensitive configuration information. From the tool's own definition: "Tool name 'list_available_extensions' indicates a listing/query operation with no side effects. The tool retrieves information about available PostgreSQL extensions without modifying any data." ## Use case AI agents call list_available_extensions to retrieve information from Mcpg without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere. ## Recommended policy (PolicyLayer) Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Mcpg: ```json { "version": "1", "default": "deny", "tools": { "list_available_extensions": {} } } ``` ## Other tools on Mcpg (251) - `cancel_migration` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/cancel-migration.md - `drop_graph` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-graph.md - `drop_property_graph` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-property-graph.md - `drop_publication` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-publication.md - `drop_subscription` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/drop-subscription.md - `dump_database` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/dump-database.md - `partman_drop_partition` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/partman-drop-partition.md - `prune_audit_events` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/prune-audit-events.md - `restore_database` — Destructive — https://policylayer.com/tools/io-github-devopam-mcpg/restore-database.md - `cancel_query` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/cancel-query.md - `cluster_vectors` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/cluster-vectors.md - `complete_migration` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/complete-migration.md - `dry_run_ddl` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/dry-run-ddl.md - `enable_extension` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-extension.md - `enable_logical_replication_on_demand` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-logical-replication-on-demand.md - `enable_redis_fdw` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/enable-redis-fdw.md - `generate_graph_projection` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/generate-graph-projection.md - `generate_test_data` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/generate-test-data.md - `hybrid_search` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/hybrid-search.md - `maintain_turboquant_index` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/maintain-turboquant-index.md - `mmr_search` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/mmr-search.md - `open_cursor` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/open-cursor.md - `optimize_query` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/optimize-query.md - `partman_run_maintenance` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/partman-run-maintenance.md - `pg_search_run` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/pg-search-run.md - `prepare_migration` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prepare-migration.md - `prewarm_recommended` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prewarm-recommended.md - `prewarm_relation` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/prewarm-relation.md - `recommend_redistribute` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/recommend-redistribute.md - `reindex_pg_search_index` — Execute — https://policylayer.com/tools/io-github-devopam-mcpg/reindex-pg-search-index.md - …and 221 more: https://policylayer.com/tools/io-github-devopam-mcpg.md ## For agents This record is a snapshot. Live verdicts and the full registry: - Check every server in your MCP config at once: `npx -y policylayer stack` - Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md) - Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events` --- Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-devopam-mcpg · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-devopam-mcpg