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

Annotations only say readOnly=false/destructive=false, so the description carries the burden, and it is unusually thorough: it discloses what is copied (sync-manifest fields) vs. reset (mechanical/build data), post-spawn cascade behavior, campaign assignment replication, one-sheet-per-ruleset constraint, and error responses. No annotation contradiction.

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?

The purpose is front-loaded, and the subsequent sentences each add distinct value: scope of copied data, sync semantics, campaign replication, error codes, and the clone contrast. Although long, it is dense rather than padded, appropriate for a tool with this complex behavior.

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 create tool with only two params and no destructive behavior, the description covers invocation constraints, identity rules, post-spawn behavior, and failure modes. An output schema exists, so return-value detail is not required; nothing needed to call it correctly 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?

Schema coverage is 100% and both parameter descriptions already document ownership, 'must differ,' restricted-ruleset grants, and list_rulesets. The description reinforces these and adds linkGroup context, but it does not substantially change parameter meaning beyond what the schema provides.

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 opens with a specific verb and object: 'Create a linked sibling sheet for a character the user owns, in a different ruleset,' and explains the linkGroup tie and multiple-ruleset persona. It explicitly differentiates from vault_clone_character, which deep-copies, so an agent can distinguish the two at a glance.

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 states when to use this tool (creating linked multi-ruleset sheets) and explicitly names the closest alternative with the deciding difference: 'This is NOT vault_clone_character — clone deep-copies the whole ruleset-specific sheet; spawn deliberately does not.' Error semantics (409/403/404) also tell the agent when a call is inappropriate.

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