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

Annotations cover the safety profile (idempotentHint=true, destructiveHint=false, readOnlyHint=false), and the description goes further by disclosing the at-least-once delivery model and the auto-ack behavior of non-peek reads. It does not discuss what happens to an already-acked or stale cursor, but the delivery semantics it does provide are substantive.

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: purpose first, then the canonical workflow, then the negative case. Zero filler and the routing information is front-loaded.

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 and only three fully documented parameters, the description supplies everything an agent needs: the ack semantics, the paired tool, and the condition under which this call is unnecessary.

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%, so the schema already explains cursor, watch_id and client_token in detail. The description only ties 'the cursor get_changes returned' to the workflow and adds nothing about watch_id scoping or the optional token. Baseline 3 is appropriate.

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 ('Mark changes up to a cursor as processed') and immediately distinguishes itself from the sibling get_changes by naming the peek/non-peek interaction. An agent can tell exactly what state this mutates without opening the schema.

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?

Explicitly prescribes the workflow (peek, act, then ack the returned cursor) and explicitly states the exclusion: 'Not needed if you call get_changes without peek (that acknowledges automatically).' Both the when and the when-not are covered with no inference required.

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