fix(x402): discovery filters out all v2 resources (12,915 of 14,668)

[aoleg8525-ai]

Description

discover_x402_services currently returns no v2 resources at all.

getResourceDescription (action-providers/x402/utils.ts) reads v2 descriptions
only from metadata.description, but the CDP discovery API returns the description
at the top level of the resource. filterByDescription therefore sees an empty
string for every v2 resource and filters all of them out, so agents only ever see
v1 results.

Measured against the default facilitator (cdp) on 2026-08-05:

	resources
total in /discovery/resources	14 668
x402 v2	13 074
v2 carrying metadata.description (what the filter reads)	0
v2 carrying a top-level description (what the API returns)	12 915
surviving filterByDescription today	1 594 (10.9 %) — all v1

Reproduce in a minute (no key needed):

node -e '
const B="https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources";
(async()=>{const all=[];let o=0,t=null;
 while(true){const j=await (await fetch(`${B}?limit=1000&offset=${o}`)).json();
  all.push(...j.items);t=j.pagination.total;o+=j.items.length;if(o>=t)break;}
 const v2=all.filter(r=>r.x402Version===2);
 console.log("total",all.length,"| v2",v2.length,
  "| v2 with metadata.description",v2.filter(r=>r.metadata?.description).length,
  "| v2 with top-level description",v2.filter(r=>r.description).length);})()'

The fix reads the top-level field first and keeps metadata.description as a
fallback, so both shapes work and v1 handling is untouched.

Tests

Added action-providers/x402/utils.test.ts (8 cases) covering both shapes and the
regressions around them:

• v2 with a top-level description → kept (fails before this change)
• v2 with metadata.description → kept (backward compatibility)
• v2 with both → top-level wins, and filterByKeyword matches it
• v2 with neither → dropped
• the "Access to protected content" placeholder → dropped
• v1 with accepts[].description → kept, unchanged

Before: Tests: 3 failed, 5 passed, 8 total
After:  Tests: 8 passed, 8 total

Run:

cd typescript/agentkit && npx jest --testMatch='**/x402/utils.test.ts'

eslint, prettier --check and tsc --noEmit are clean on the touched files.
A patch changeset is included.

Note on the manual chatbot walkthrough the template asks for: the change is inside
a pure filter with no wallet or network interaction, and the discovery counts above
come from the live default facilitator rather than a local run.

[cb-heimdall]

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