Harness spec 3.0.0-draft: the memory resource a device reads, by name

acp.md said a logged-in device reads "the resource holding the entries for
the prompt" without naming it, so neither side could implement it. It is
`lembas://memory`: the entries as the memory block of a system prompt shows
them, read as a session starts and kept for it. Only `memory` is taken from
/mcp — notes, knowledge bases and skills stay the device's; the scope rides on
the resource read as on the tool call; a token's older `library` scope counts
as `memory`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

harness/acp.md

@@ -580,11 +580,16 @@ Besides `/v1/models`, the chat completions, `/api/v1/instance` and `/mcp`:
 
 - **Memory** (spec 3.0.0): memory records are the instance's, for the device as for a chat. Logged
   in to an instance whose token has the `memory` scope, the CLI's `memory` tool and the memory it
-  puts into the prompt are the instance's records, read and written through `/mcp` (`memory`, and
+  puts into the prompt are the instance's records, read and written through `/mcp`: the tool
-  the resource holding the entries for the prompt). A call made for a session the client opened
+  `memory` (the spec's, `tools/memory.json`), and the resource **`lembas://memory`**, whose text is
-  carries `params._meta.lembas.scope: <sessionId>` and lands in that chat's data group; a session of
+  the entries as the memory block of a system prompt shows them (empty: none), which the device
-  the device's own lands in the data group of the session's model. Local memory files are not
+  reads as a session starts and keeps for that session (the prompt does not change under a
-  synced up; logged out, there is no memory.
+  session). Only `memory` is taken from `/mcp`: notes, knowledge bases and skills stay the device's
+  own. A call made for a session the client opened carries `params._meta.lembas.scope:
+  <sessionId>` (on the tool call and the resource read alike) and lands in that chat's data group;
+  a session of the device's own lands in the data group of the session's model. A token with the
+  older `library` scope counts as `memory`. Local memory files are not synced up; logged out, there
+  is no memory.
 
 ## Notes