portal-router — cross-agent capability resolution

When capabilities are spread across many agent ecosystems (Claude, Codex, Gemini, OpenCode, OpenClaw, a shared .agents pool, a skills distribution), the expensive question is no longer "how do I do X" but "which of my agents already has a skill for X, and how do I load it?" portal-router answers that from one place.

It treats every ecosystem as a capability source, normalizes their heterogeneous unit shapes into one record, ranks matches against an intent, and loads the chosen unit. It is the skill an orchestrator reaches for before authoring a new skill — to check whether the fleet already owns the capability.

When to use

"Which agent has a skill for PDF extraction / k8s / data cleaning?"
"Find me a capability that does Y" — across all agents, not just the current one.
Before forging a new skill: confirm the fleet doesn't already have one.
Routing a task to whichever agent owns the right tool.

The load-path

The reference implementation is the operator's ~/_arms/arm portal (the _arms cross-agent skill ecosystem). It exposes:

arm find <query…>        # rank capabilities across ALL ecosystems by relevance
arm list [ecosystem]     # the portal index (computed live; never stale)
arm show <eco> <name>    # LOAD one capability through the portal (prints its body)
arm status               # portal health

Example — find a capability regardless of which agent owns it, then load it:

arm find pdf extraction
arm show claude pdf-processing      # capability loaded through the portal into context

How it resolves (the engine)

references/resolve.py (stdlib-only Python — no dependencies) is the portable engine. It:

Discovers every ecosystem's skill home (following symlinks — find -L / followlinks=True; the mirror entries are symlinks, and without following them the portal reads as empty — the single load-bearing detail).
Normalizes heterogeneous units — Claude/Codex/Gemini SKILL.md dirs with YAML frontmatter, OpenCode flat command .md (name = filename), a-i--skills *.skill/category dirs — into one {ecosystem, type, name, description, path, invoke} record.
Ranks matches (name > triggers > description > path) and, on show, prints the unit plus the exact invoke hint for that agent's own loader.

Point it at any directory of ecosystems (default ~/_arms/mirror/ + ~/_arms/skills/) and it indexes them live. The index is computed each call from the sources, so it can never drift from reality — there is no stored index to stale.

Honest about reach

For same-agent units (e.g. Claude loading a Claude SKILL.md), show is a real context-load. For other agents it prints the unit and the precise invoke hint for that agent's loader — the portal routes you to the door; each agent still opens its own. Cross-agent execution is the orchestrator's job (see agent-swarm-orchestrator); portal-router is the discovery-and-routing layer beneath it.