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

Annotations already establish that this is a safe, read-only, closed-world lookup, so the bar is lower. The description adds genuine value by disclosing what the response contains (top memories, relationships, aliases), which is important given there is no output schema; it stops short of noting behavior when a key resolves to nothing or how many 'top memories' are returned.

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, front-loaded with the action and resource before the parenthetical detail. The entity-type list is slightly long but earns its place by conveying lookup breadth, and there is no filler or redundancy.

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 one-param, read-only lookup with no output schema, the description supplies the return shape, matching rule, and entity scope, which is enough to call it correctly. Minor gaps remain around not-found behavior and the size/ordering of returned collections, but nothing essential is missing.

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?

Only one parameter and schema coverage is 100%, so the schema already documents 'key' as 'the entity's canonical key or name.' The description's 'Match by canonical key or name' largely restates that and adds no new format or resolution semantics, so the baseline 3 applies.

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?

Specific verb ('Return') plus specific resource ('the full profile for one entity') with an enumeration of contents (top memories, relationships, aliases) and entity kinds. The single-entity scope plus the content list implicitly separates it from aggregate/sibling tools like get_brain_index, memory_stats, and search.

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?

The description never says when to reach for this tool versus search, recall_memories, or search_notes, nor any exclusions or prerequisites. 'Match by canonical key or name' is an input hint, not usage guidance, so the agent must infer the use case.

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