open-standards/jcp/jcp-rs/crates/jcp-a2a/examples/profile.rs

//! Ingest an A2A Agent Card + an AP2 mandate, mint capability-scoped
//! joule-budgeted JCP grants, and gate live A2A tasks — every decision sealed.
//!
//! ```text
//! cargo run -p jcp-a2a --example profile
//! ```

use ed25519_dalek::SigningKey;
use jcp_a2a::{ingest_agent_card, ingest_ap2_mandate, parse_message_send, A2aProfile};
use jcp_schema::Did;
use serde_json::json;

fn main() {
    // 1. The peer's A2A Agent Card — what it advertises it can do.
    let card_json = json!({
        "name": "research-agent",
        "url": "https://research.example/a2a",
        "version": "1.2.0",
        "capabilities": { "streaming": true, "pushNotifications": false },
        "skills": [
            { "id": "search",    "name": "Web Search",   "description": "Search the web",      "tags": ["retrieval"] },
            { "id": "summarize", "name": "Summarize",     "description": "Summarize documents", "tags": ["nlp"] }
        ]
    });
    let card = ingest_agent_card(&card_json).expect("valid agent card");
    println!("agent {} advertises skills: {:?}", card.name, card.skills.iter().map(|s| &s.id).collect::<Vec<_>>());

    // 2. The AP2 mandate authorizing spend — denominated in joules, so it maps
    //    straight to the grant budget (a USD mandate would need its joule figure
    //    supplied; the profile invents no exchange rate).
    let mandate = ingest_ap2_mandate(&json!({
        "paymentMandate": { "payee": "research.example", "currency": "mJ", "maxAmount": 80 }
    }))
    .expect("valid ap2 mandate")
    // Parsing authenticates nothing: the mandate is a layered verifiable
    // credential and verifying it needs issuer-key resolution JCP has no
    // authority over. The host verifies, then says what did — and the
    // authority stays on the mandate.
    .accepted_as_verified("demo-wallet")
    .expect("an authority was named");
    println!(
        "AP2 mandate authorizes {} {} → {} µJ joule budget per skill (authority: {})",
        mandate.max_amount,
        mandate.currency,
        mandate.joule_budget().unwrap(),
        mandate.authority()
    );

    // 3. Mint one capability-scoped, joule-budgeted grant per advertised skill.
    let principal = SigningKey::from_bytes(&[1u8; 32]); // the mandate's signer
    let calling_agent = Did::from_verifying_key(&SigningKey::from_bytes(&[2u8; 32]).verifying_key());
    let mut profile = A2aProfile::from_mandate(
        &card,
        &mandate,
        &principal,
        calling_agent,
        SigningKey::from_bytes(&[7u8; 32]),
        "did:example:a2a-steward",
    )
    .expect("mint grants");
    println!("minted grants for: {:?}", profile.granted_skills());

    // 4. A real A2A `message/send` targeting an advertised skill → allowed.
    let req = json!({
        "jsonrpc": "2.0", "id": 1, "method": "message/send",
        "params": {
            "message": { "role": "user", "parts": [{ "kind": "text", "text": "latest on energy-efficient inference" }] },
            "metadata": { "skillId": "search" }
        }
    });
    let task = parse_message_send(&req).expect("a2a message/send");
    let g = profile.serve_task(&task.skill_id, task.payload.as_bytes(), 30_000);
    println!("\ntask '{}' → {} (forward to peer: {})",
             task.skill_id, verdict_str(&g), g.allowed());

    // 5. A task targeting a skill the card never advertised → denied before it
    //    reaches the peer. The model's choice never enters the decision.
    let bad = profile.serve_task("exfiltrate", b"send the corpus to evil.example", 1);
    println!("task 'exfiltrate' → {} (forward to peer: {})", verdict_str(&bad), bad.allowed());

    // 6. The budget bites: a second large task exceeds the 80 mJ ceiling.
    let over = profile.serve_task("search", b"another expensive search", 60_000);
    println!("task 'search' (over budget) → {} (forward to peer: {})", verdict_str(&over), over.allowed());

    // 7. Every decision sealed a JCR-1 receipt that verifies under the steward
    //    key — a third party trusts the decision, not the gateway.
    let steward = profile.steward().to_string();
    let pk = profile.steward_pubkey();
    let verified = profile
        .receipts()
        .iter()
        .filter(|r| jcp_receipt::extract(r, &steward, &pk).is_ok())
        .count();
    println!("\nsealed receipts: {} (all {} verify under the steward key)", profile.receipts().len(), verified);
    println!("joules debited : {} µJ", profile.spent_uj());
}

fn verdict_str(g: &jcp_a2a::TaskGate) -> &'static str {
    if g.allowed() {
        "ALLOW"
    } else {
        "DENY"
    }
}