Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Well beyond the annotations, it discloses that full history is preserved, that duplicate calls create extra revisions without corrupting data (consistent with idempotentHint=false), that tags and conversations are additive rather than replacing, that a soft-deleted memory is silently revived with restoredFromDeleted: true, and that setting canon_status 'accepted' clears supersession pointers. The content policy adds an explicit prohibition boundary the annotations cannot express. Nothing here contradicts readOnlyHint=false or destructiveHint=false.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Long but disciplined: it front-loads the core mutation and revision semantics, then groups secondary behavior under labeled blocks (SOFT-DELETE RESTORE, SUPERSESSION CLEANUP, CONTENT POLICY). Each block addresses a distinct decision an agent must make, and the retryability note is a single compact sentence.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 19-parameter mutation tool with nested signer and conversation objects, the description covers the highest-risk semantics (history, restore, supersession, content restrictions) and an output schema exists so return values need not be spelled out. Gaps remain around the mode enum's practical selection and the collection-move precondition, both of which rest on schema text alone.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3; the description earns above that by explaining cross-parameter behavior the schema cannot — that tags and conversations are additive, and that superseded_by: null is the explicit pointer-clearing mechanism while canon_status 'accepted' clears it as a side effect. It leaves mode/append_mode selection and the collection move constraint to the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence names a specific verb and resource ('Update an existing memory by creating a new revision') and clarifies the revision semantics that distinguish it from a naive in-place write. It further enumerates the in-place mutable fields (kind, canon_status, confidence, verification_status), letting an agent separate this from siblings like memory_supersede or memory_bulk_update without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives clear conditions for specific paths: soft-deleted targets are revived by any successful update, which it identifies as the supported undelete path alongside the restore endpoint, and it explains how to clear supersededBy (set canon_status 'accepted' or pass superseded_by: null). It does not, however, route the agent between this tool and siblings such as memory_supersede or memory_bulk_update, nor does it advise when to prefer body_append over body_replace.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.