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

Annotations already declare this is a non-readonly, destructive mutation, so the safety profile is covered. The description adds no behavioral detail beyond that: it doesn't say whether this is a partial update (omitted fields preserved), whether it requires being the rock owner, whether changes are reversible or audited, or why destructiveHint is true for a status change.

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 short sentences, front-loaded with the mutation and its fields, followed by the usage context. No filler.

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 4-parameter mutation with annotations present and no output schema, the description is minimally adequate but leaves key calls unanswered: partial-update semantics, ownership/permission requirements, and return/confirmation behavior.

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 50% (completed and status_note described in the schema; rock_id and on_track undocumented). The description names all three updatable fields but adds no meaning beyond the names — nothing on how on_track and completed interact, or what happens when only some fields are supplied.

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?

Uses a specific verb ('Update') plus resource ('a rock') and enumerates the mutable fields: on_track flag, status note, completion. It is clearly distinguished from add_rock/list_rocks by being the mutation path, though it does not name siblings 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?

The sentence 'Used during the weekly Delta Meeting rock review' gives temporal context for when to call it, which is more than nothing. But there is no guidance on when not to use it, no mention of add_rock for creation, and no prerequisites (rock ownership, meeting state).

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