docs: add LLM-Friendly Docs section and enhance ERC-8004 documentation

Author: tenequm

docs/.vitepress/config.ts

@@ -73,6 +73,14 @@ export default defineConfig({
           { text: 'Compute Unit Benchmarks', link: '/advanced/benchmarks' },
         ]
       },
+      {
+        text: 'LLM-Friendly Docs',
+        collapsed: true,
+        items: [
+          { text: 'llms.txt', link: '/llms.txt' },
+          { text: 'llms-full.txt', link: '/llms-full.txt' },
+        ]
+      },
     ],
 
     socialLinks: [

docs/erc-8004.md

@@ -11,6 +11,40 @@ SATI is ERC-8004 on Solana. Full feature parity with the standard, plus Solana-n
 
 [[toc]]
 
+## How SATI Relates to ERC-8004
+
+ERC-8004 is the standard. SATI is an implementation of that standard on Solana, with Solana-native extensions on top.
+
+Think of it like this: ERC-8004 defines *what* agent identity infrastructure should look like - registration, reputation, validation, and a shared registration file format. SATI implements all of that using Solana's primitives (Token-2022 for identity, Light Protocol for storage, Photon for indexing) and adds capabilities that the standard leaves to implementers.
+
+### What's the same
+
+- **Registration file format** - same JSON schema, same field names, same CAIP-2 identifiers. An ERC-8004 registration file on Base and a SATI registration file on Solana are interchangeable.
+- **Feedback fields** - `value`, `valueDecimals`, `tag1`, `tag2`, `endpoint` map directly between ERC-8004 and SATI. See [Feedback Field Mapping](#feedback-field-mapping) below.
+- **Cross-chain identity** - agents can be registered on both chains simultaneously, linked via the `registrations` array in the shared registration file.
+
+### What SATI adds
+
+ERC-8004 defines the interfaces and leaves implementation choices to each chain. SATI makes three specific choices that extend the standard:
+
+**1. Optional proof of participation (FeedbackV1)**
+
+ERC-8004's `giveFeedback()` is an open model - any reviewer can submit feedback about any agent. SATI implements this as FeedbackPublicV1 (the default). On top of that, FeedbackV1 adds an optional dual-signature flow where the agent cryptographically commits to the interaction before knowing the feedback outcome. This makes feedback verifiable by on-chain programs - useful for DeFi composability, escrow, and automated trust decisions.
+
+Both models coexist. FeedbackPublicV1 is the ERC-8004 compatible default. FeedbackV1 is available when stronger guarantees are needed.
+
+**2. Native indexing via Photon**
+
+On EVM, querying "all feedback for agent X" typically requires an external indexer like The Graph - a separate service with its own trust assumptions and operational cost. On Solana, Photon RPC indexes compressed accounts natively. Every RPC provider that supports Light Protocol serves this data as a standard RPC call, with no additional infrastructure to deploy or maintain.
+
+**3. Cost-predictable compressed storage**
+
+Every feedback interaction is stored individually on-chain at ~$0.002 via ZK Compression - not just aggregated summaries. This cost is stable regardless of network conditions. On EVM L2s, per-transaction costs are comparable at current gas prices but vary with network congestion.
+
+### Can agents exist on both?
+
+Yes. An agent registered through SATI on Solana and through ERC-8004 on Base can share the same registration file, the same services, and the same identity. The `registrations` array in the registration file links identities across chains using CAIP-2 identifiers. See [Cross-Chain Agent Identity](#cross-chain-agent-identity) below.
+
 ## What's Compatible
 
 SATI implements every component of the ERC-8004 specification: