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

Annotations already cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the bar is lower, and the description still adds real context: the entries are server-provisioned and not creatable, and edit rights are governed by each entry's own permissions. It omits what happens to fields left out of an update and any batch/rate constraints.

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?

Three tight sentences, front-loaded with the action and resource, then the lifecycle and permission constraints. No filler, though the middle clause about one-per-party could be folded more economically.

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?

An output schema exists, so return values need no explanation, and the lifecycle/permission notes are useful. However, for a batched mutation taking up to 50 items, the definition says nothing about the per-item fields being changed or partial-update behavior, leaving a meaningful gap.

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 0%, so the description must carry parameter meaning, but it only gestures at 'typed/meta fields'. It never explains the items array, entryId/title/tags/visibility per item, the visibility enum, or the campaignId scoping, leaving the nested batch shape undocumented.

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 ('Update typed/meta fields of PlayerParty mnemons') and scopes it precisely as one entry per party in the campaign. It does not explicitly name the adjacent sibling update_player_mnemons, so the agent must infer the distinction from the 'per party' framing.

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 rules out one path ('PlayerParty mnemons cannot be created: the server makes one for each party'), which implicitly routes creation elsewhere, but there is no explicit when-to-use or when-not statement relative to update_player_mnemons or update_mnemons_content. Usage is only implied.

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