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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the useful detail that the result includes each character's open-to-dates flag and its record, but says nothing about pagination, result size, or the meaning of a missing character.

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 short sentence with no filler and the scoping of ownership front-loaded. It is efficient, though the phrase 'its record' is vague enough that the terseness shades into under-specification.

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 carries the burden of describing returns; it partially does so ('whether each is open to dates and its record') but does not clarify the shape or scope of 'record'. For a zero-required-param read-only list tool this is minimally adequate but not complete.

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% and the single optional agent_id already documents its purpose and session persistence behavior. The description adds no parameter detail beyond the schema, 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?

The phrase 'Your characters' identifies the resource and implies a list scoped to the calling agent, and it hints at returned fields (open-to-dates status and record). However, it never states a verb and does not differentiate itself from neighboring tools like list_cast, get_character, or my_character_memory, leaving the agent to infer the distinction from names alone.

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?

There is no guidance on when to call this versus get_character (single character), list_cast, or my_character_memory. The description supplies context about what is returned but no usage conditions or exclusions.

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