docs: add ERC-8004 interop documentation

[kawacukennedy]

This PR adds documentation for the ERC-8004 (Kuberna Labs) interop with AIP, as discussed in issue #1.

Changes:

1. docs/competitive-analysis.md: New section for ERC-8004 with status, strengths, limitations, and AIP relationship describing how the two protocols complement each other (off-chain fast path via AIP, on-chain durable record via ERC-8004). Also adds ERC-8004 entry to the Other Emerging Projects comparison table.

2. spec/aip-core.md: Adds erc8004 extension field example to the identity document JSON schema, updates the extensions field description, and adds ERC-8004 to the design decisions note.

Interop pattern: An AIP identity document can include an erc8004 extension linking to an agent's on-chain registration, while an ERC-8004 delegation can reference an AIP token's scope as off-chain context. The adapter library consuming AIP as a primitive will live in the Kuberna Labs repos (separate PR).

Summary by CodeRabbit

Release Notes

• Documentation
  • Enhanced competitive analysis with comprehensive coverage of ERC-8004 (Trustless Agents), including its capabilities, limitations, and integration approach with agent infrastructure protocols. Updated references to include ERC-8004 specification.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

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Run ID: 83b8b33b-ce6a-416c-bc81-14a4acd51ecb

📥 Commits

Reviewing files that changed from the base of the PR and between 9ea8964 and c486604.

📒 Files selected for processing (1)

• docs/competitive-analysis.md

✅ Files skipped from review due to trivial changes (1)

• docs/competitive-analysis.md

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📝 Walkthrough

Walkthrough

This PR adds documentation for ERC-8004 (Trustless Agents) to the competitive analysis guide. A new subsection describes the protocol's draft status, on-chain strengths, and limitations, then explains how it complements AIP through off-chain and on-chain layers. The document updates the emerging projects table and adds a reference link.

Changes

ERC-8004 Competitive Analysis

Layer / File(s)	Summary
Competitive analysis and references docs/competitive-analysis.md	New ERC-8004 subsection describes protocol status, on-chain strengths (agent identity, recording, audit trail), limitations (EVM-only, gas costs, no MCP/A2A/HTTP bindings), and planned AIP adapter; adds corresponding table row and reference entry.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

📜 A rabbit hops through protocol lands,
Finding ERC-8004 at helpful hands—
On-chain trust meets off-chain speed,
Two paths forward, one strong seed!
Documentation grows, the way is clear. 🌿

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately reflects the primary change: adding documentation for ERC-8004 interoperability. The raw summary confirms new subsections and references for ERC-8004 were added to the competitive analysis document.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@docs/competitive-analysis.md`:
- Around line 128-143: Add a primary source link for ERC-8004 by inserting the
official EIP/spec/repo URL into the ## References section and then cite it
inline next to the "Status: Draft EIP, active development." line and the later
"ERC-8004" mention; specifically, update the text that includes "Status: Draft
EIP, active development." and the paragraph referencing "ERC-8004" to include a
parenthetical or bracketed citation pointing to the new References entry so the
deployment/status and claims are verifiable.

In `@spec/aip-core.md`:
- Around line 120-122: Add a small normative subsection that defines
extensions.erc8004: require an object with required keys "chain_id" (positive
integer) and "address" (string containing a 20-byte hex Ethereum-style address,
prefixed with 0x and validated as hex; optionally state checksum/case rules),
and allow an optional "metadata" object for freeform fields; specify types,
example JSON, and a short validation rule (e.g., JSON Schema fragment or
explicit bullet rules) and apply this definition wherever extensions.erc8004 is
referenced (the three occurrences) so producers/consumers can interoperate using
the functions/constructs named extensions.erc8004, chain_id, and address.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 9a4dcd6c-2b9f-4c9e-9058-b9d838214f9a

📥 Commits

Reviewing files that changed from the base of the PR and between b3dc854 and a996e2e.

📒 Files selected for processing (2)

• docs/competitive-analysis.md
• spec/aip-core.md

[kawacukennedy]

Addressed both CodeRabbit review comments in commit 9ea8964:

1. ERC-8004 citation — Added [ERC-8004] reference link to the References section pointing to the EIP draft, and cited it inline at both the status line ("Status: Draft EIP, active development [ERC-8004]") and the relationship paragraph.

2. Normative extensions.erc8004 schema — Added Section 3.2.1 defining:

   • chain_id (REQUIRED, positive integer, EIP-155 chain ID)
   • address (REQUIRED, 20-byte hex with 0x prefix, checksum optional)
   • metadata (OPTIONAL, freeform object)
   • Validation rules, forward compatibility, and extension semantics
   • JSON example matching the existing identity document in Section 3.1

[sunilp]

Thanks for following up from #1. The competitive-analysis content is useful and I want to land it, but two changes first.

1. Drop the spec/aip-core.md changes. #1 scoped this to docs. A normative extension schema shouldn't land in the core spec before a working adapter exists to prove what the schema actually needs. Once your adapter runs against the spec we can revisit a non-normative example.

2. Fix the attribution. ERC-8004 is an Ethereum ERC (Trustless Agents), not a Kuberna Labs project. Retitle the section "ERC-8004 (Trustless Agents)" and cite the EIP directly. Kuberna Labs can have one line as a third-party adapter in development. I'll add the link when it works against the spec, as agreed in #1.

Happy to merge the docs change with those two fixes.

[kawacukennedy]

The requested changes are addressed in commit c486604:

• ✅ Dropped spec/aip-core.md changes (only docs/competitive-analysis.md remains)
• ✅ Fixed attribution: retitled to "ERC-8004 (Trustless Agents)" citing the EIP directly
• ✅ Kuberna Labs is mentioned only as a third-party adapter in development

Ready for re-review.