feat(sicore-a2a-mcp): support multiple named A2A keys selected by alias

[LikiosSedo]

Problem

One sicore-a2a-mcp adapter process binds a single A2A key, i.e. a single Siclaw agent. Switching agents means editing config and restarting. The obvious shortcut — passing the key as a tool argument — is exactly the thing we must not do: A2A keys are credentials and must never flow through the model context.

Approach

Put multiple named keys in configuration, and let the model select an agent by a short alias passed as an optional agent tool argument. The alias is the only agent selector that crosses the model boundary; keys stay in config/env only.

Changes

• Config — new SICLAW_A2A_KEYS env, a JSON object {"alias":"sk-..."}. Aliases must match ^[a-z0-9][a-z0-9_-]{0,31}$.
  • Backward compatible: SICLAW_A2A_KEY / SICLAW_A2A_KEY_FILE keep working and map to the reserved alias default. The two forms may be combined; a default alias inside SICLAW_A2A_KEYS is a collision error.
  • SICLAW_AGENT_ID still pins the default single key; combining it with SICLAW_A2A_KEYS is rejected (each named key resolves its own agent).
  • Every key is self-resolved once at startup via GET /api/v1/a2a/self; any failure aborts boot with the failing alias named (fail-fast, no silent partial key).
• Tool surface — all five tools gain an optional agent alias argument (never a key). Descriptions are populated at startup with the configured aliases and their resolved agent ids. One agent → agent optional; several → omitting it on a create/list call errors with the alias list instead of guessing.
• Routing — task_id/context_id are per-key server resources. The adapter records task_id -> alias in process memory, so siclaw_wait_task / siclaw_get_task / siclaw_cancel_task auto-route to the creating key. A mismatched agent argument is overridden by the recorded creator and a routing_note records the override. siclaw_list_tasks without agent aggregates across every key, tags each row with its alias, and rebuilds the map after a restart.
• Security — keys live only in configuration. They are never a tool parameter, never logged, and never present in an error message; errors and the stderr ready line carry aliases and resolved agent ids only.

Implementation routes the new logic through a small AgentRouter; SicoreA2aClient stays per-key and unchanged.

Scope

The remote Sicore MCP endpoint (/api/v1/mcp) is out of scope: each remote client config carries its own Authorization header, so multi-agent there is just multiple client configs. This alias multiplexing is only for the local stdio adapter that injects credentials from env/files. The README documents this split.

Tests

npm test — 56 passing (was ~30).

• Config: multi-key parse/order, single-key default mapping, merge, alias validation, collision, SICLAW_AGENT_ID + SICLAW_A2A_KEYS rejection, non-string/malformed key values not echoed.
• Router unit tests: selection rules, task→creator precedence + override note, untracked-task attribution.
• Tool tests: single-key back-compat behavior preserved, multi-key requires agent, unknown alias, named routing, auto-route follow-ups, override note, aggregated list, ownership recovery.
• stdio e2e: existing single-key + self-resolve tests, plus a new two-alias cold-start smoke asserting per-key /self resolution, description injection, alias routing, and no key leakage in descriptions or the stderr ready line.

Manual fail-fast smoke confirmed for missing key / bad alias / collision / SICLAW_AGENT_ID+SICLAW_A2A_KEYS — each exits 1 with a clear message and no key echoed.

Not published: no npm publish, no tag — release is left to the maintainer.