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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds little beyond that: it says results are scoped to 'this user's memories' and include counts and last activity, but since an output schema exists, those return details are partly redundant and no pagination or volume limits are mentioned.

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?

Two sentences, zero filler, and the primary behavior (grouping with counts and last activity) is front-loaded ahead of the usage advice. Every clause carries 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 an output schema and rich annotations already present, the description only needs to orient the agent, and it does: scope, grouping modes, payload, and use cases. Minor gaps (whether entities are global or per-source, expected result volume) keep it from a 5, but nothing essential is missing for correct invocation.

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 coverage is 100%, so the baseline is 3, but the description earns a notch above by mapping the three grouping choices to plain-language axes (origin source, extracted category, extracted type), reinforcing the enum's meaning before the agent opens the schema. It still doesn't mention the omit-to-return-all default, which the schema carries alone.

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 description gives a specific verb (group/list) and resource (this user's memories as entities), and defines what an 'entity' is by naming the three grouping axes: origin source, extracted category, extracted type. It also states the payload (counts and last activity), which distinguishes it from list_memories and search_memory.

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 two concrete use cases: 'see what is stored before searching' and 'find an entity to delete'. The first implicitly routes against search_memory, and the second toward delete_entity. No explicit when-not or named alternative, so it stops short of a 5.

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