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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description goes beyond that by disclosing what is computed (counts, per-project and per-type breakdowns, last activity date), which tells the agent the shape and limits of the response.

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?

A single sentence, front-loaded with the verb and followed by the enumerated metrics. No filler, no restatement of the title, every clause adds information.

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?

With no output schema, the description must carry the return-value burden, and it enumerates the metrics well. It stops short of describing the concrete shape of the breakdowns (flat map vs. nested) and whether counts are scoped to the current user only, which is a minor remaining gap.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline for a parameterless tool is a 4; the description correctly makes no false promise of filtering arguments.

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?

States a specific verb ('Returns counts') and resource ('the user's memory'), and enumerates exactly what is counted: total, active, archived, breakdowns by project/type, last activity date. This clearly separates it from content-returning siblings like memory_list or memory_search, though no sibling is named explicitly.

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?

Usage is only implied: an agent can infer this is the overview/aggregate call rather than a content-retrieval call. There is no explicit 'use when' statement and no named alternative such as memory_list for actual memory content.

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