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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds real value beyond them by disclosing the failure mode: private and followers-only profiles return not found, which an agent must anticipate for error handling. No auth or rate-limit context is given.

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 tight sentences: the returned-field inventory comes first, then the access limitation. No filler and nothing redundant with the annotations.

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 single-param read tool with no output schema, the description compensates by enumerating the returned profile fields and stating the not-found behavior for restricted profiles — the two things an agent needs that structured fields do not provide.

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% and the handle property already documents 'without the @'. The description's 'by handle' restates the schema rather than adding syntax, validation or normalization rules, so 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+resource: 'A trader's public profile by handle', followed by an enumeration of the returned fields (user id, bio, avatar, follower/following counts, join date). That clearly separates it from siblings like get_trader_activity, get_trader_portfolio and list_traders, 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 implied by 'by handle' and the field list, but there is no explicit statement of when to pick this over get_trader_portfolio/get_trader_activity or what happens when the caller only has a display name. The private/followers-only clause is behavioral, not routing guidance.

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