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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds real context on top: a GM-only authorization gate, the fact that HUD removal changes membership, and that values are 'live' rather than snapshotted. It does not cover ordering, size, or what the 'numbers' actually are, but the bar is lower given full annotation coverage.

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?

Front-loaded with the payload ('Every standing character on the Master HUD') and every clause carries information except the final 'Returns: The party.', which is circular filler. Short and scannable overall.

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 is the only source for what comes back, and 'Returns: The party.' restates the tool name rather than describing shape, fields, or the 'live numbers'. Membership and permission semantics are covered well enough that an agent can call it, but it cannot predict the response.

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?

Single parameter at 100% schema description coverage, where the schema already explains the campaign slug-or-id convention. The description contributes nothing about the campaign parameter, 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?

States a specific verb-and-resource: retrieves every standing character on the Master HUD with live numbers, and explicitly scopes out characters removed via `set_character_on_hud`. That distinguishes it from the HUD-mutation sibling, but it does not differentiate against `list_characters` or `get_character`, which an agent would also plausibly reach for.

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?

Gives a partial usage signal: 'GM only' states a prerequisite, and the exclusion clause implies when the result differs from a full roster. It never says when to prefer this over `list_characters`, `get_character`, or `get_combat_roster`, so the agent must infer the choice from the name alone.

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