{"slug":"constant-lookup-78eaa1b3","name":"Constant lookup","summary":"Look up a physical constant by its key (e.g. \"speed-of-light\"), symbol (e.g. \"c\") or exact name. Returns the CODATA 2018 recommended value, unit, relative standard uncertainty (0 for values that are exact by SI definition) and category.","status":"live","headings":[],"indexable":false,"listed_since":"2026-10-25T17:53:27.505995Z","sources":[{"source":"x402_bazaar","external_id":"https://physics.openverbs.com/v1/constant","owner_address":"0xb3f4de103f34b99f0da19b4f16d6b53a14c2194a","seen_at":"2026-11-04T19:59:51.104234Z","removed_at":"2026-11-10T05:59:30.943143Z"}],"endpoints":[{"url":"https://physics.openverbs.com/v1/constant","host":"physics.openverbs.com","protocol":"x402","state":"live","last_probe_at":"2026-11-10T10:50:07.259558Z","last_ok_at":"2026-11-10T10:50:07.259558Z","tools_count":null,"tools_changed_at":null,"uptime_24h":1.0,"uptime_30d":1.0}],"also_listed_as":[{"slug":"physics-openverbs-com-55e23d60","name":"physics.openverbs.com"}],"payment_options":[{"endpoint_url":"https://physics.openverbs.com/v1/constant","network":"eip155:8453","scheme":"exact","rail":"exact","asset":"0x833589fcd6edb6e08f4c7c32d4f71b54bda02913","coin":"USDC","asset_label":"USD Coin","amount":"4000","pay_to":"0xb3f4de103f34b99f0da19b4f16d6b53a14c2194a","observed_at":"2026-11-10T10:50:07.259558Z"}],"usage":null,"assessment":{"method":"2026.11.2","checks":[{"id":"answers","state":"pass","reason":"Answered a check 1 hours ago."},{"id":"owner","state":"fail","reason":"No one has proven control of its domain or of the wallet it is paid at."},{"id":"track_record","state":"fail","reason":"Listed for 15 days; 30 are needed."},{"id":"real_customers","state":"fail","reason":"No source reports paying wallets in the last 30 days."},{"id":"clean_scan","state":"not_applicable","reason":"Not an MCP server."}],"passed":1,"applicable":4,"contradicted":false,"computed_at":"2026-11-10T12:40:33.111755Z"},"identity":{"endpoint_domains":["openverbs.com"],"proven_domains":[],"proven_wallets":[],"namesakes":[],"namesake_count":0,"identity_checks":[],"wallet_attestations":[],"human_backings":[]},"replies":[],"customers":null,"scan":null,"notice":"Not affiliated with addrbook — claim or request removal."}