CoinDesk is cached and has solid reputation (25% citation rate). This specific article directly covers Coinbase accepting AI agent payments via x402, which is a key real-world example of the question's core.

Stripe Blog is cached and highly relevant (agent integrations, developer controls for payments), offering a practical, non-crypto perspective on agent commerce that complements the x402-specific sources.

Decrypt is cached and relevant (AI wallet for autonomous trading), showing the wallet/infrastructure side enabling agent commerce, though less directly about x402.

Stablecoin Ledger is the top-reputation source on this subject (47% citation rate, avg weight 0.67) and is cached, so free to reuse. Its stablecoin-as-unit-of-account content directly supports the 'stable digital medium' sub-claim.

Ethereum Foundation Blog is cached and has a perfect avg weight when cited (1.0). While focused on protocol security, its coverage of AI agents interacting with Ethereum provides relevant background on on-chain agent activity. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Arc Settlement Benchmarks is cached and provides specific, technical data on x402 settlement latency, which is valuable for understanding the practical performance of the protocol in the commerce loop. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Web Payments Review is cached and offers cross-protocol commentary on settlement timing, which is useful but less directly tied to x402 and stablecoins than the Arc Benchmarks. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Cointelegraph is cached and covers Coinbase accepting USDC from AI agents, which is relevant news, but its lower citation rate (22%) and avg weight (0.43) make it less valuable than the CoinDesk article on the same topic. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Agent Economy Weekly is the second-highest reputation source (35% citation rate, avg weight 0.7) and is cached. Its direct coverage of x402 as an agent payment rail is the core of the question. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Latent.Space is cached and has a high avg weight when cited (1.0). Its coverage of ontologies for AI agents is tangentially relevant to the 'negotiate and verify' sub-claim but not directly about commerce or payments. — the 4-source attention budget is full, so lower-ranked evidence is skipped.

Distributed Systems Notes is cached and covers idempotency keys, a relevant technical detail for reliable payments, but its low citation rate (8%) and general nature make it lower priority than direct sources. — cached bytes are free, but this read does not clear the attention gate (EV 0.40, minimum 0.45, with a required claim target).

AI marketing agents article is not cached and while about AI agents, its focus on marketing operations is not directly relevant to autonomous commerce via x402 and stablecoins.

Simon Willison's Weblog on LLM tools is not cached and relevant to AI agent tooling in general, but not specifically about x402, stablecoins, or payment commerce.

Hugging Face Blog article on token efficiency is not cached and relevant to AI model optimization, not autonomous commerce or payments.

Vitalik's website on low-risk DeFi is not cached and tangentially related to Ethereum's role in finance, but not directly about AI agent commerce or x402.

The Coinbase Blog article is cached but outdated (2022 fee updates) and off-topic for the current question about x402 and AI agents.

Gardening article is cached but completely irrelevant to the question.

Retro gaming article is cached but completely irrelevant to the question.

Mystic/occult article is not cached and irrelevant to the question.