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

Annotations declare destructiveHint=true and readOnlyHint=false, so the safety profile is already partly covered; the description still adds real value by disclosing the approval flow ('May return needs_confirmation'), the ongoing credit cost of scheduled/on-publish runs, and which fields are permanently fixed after creation. It never explains what 'destructive' means here (e.g., that null clears description/schedule), leaving one gap.

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-loads the mutable fields in the first sentence, then immutability, then confirmation/credit notes — a logical order with little waste. The parenthetical glosses on each field make it slightly long, but every clause carries actionable information.

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 12-param mutation tool with no output schema, the description covers mutation scope, immutability of non-editable fields, the confirmation/approval round-trip, and the cost side effects of enabling schedules — everything an agent needs to call it correctly.

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 documents every parameter (including 'null turns alerts off' and the timezone/HH:MM formats). The description restates a few of these (threshold semantics, runOnPublish trigger) without adding new syntax or format detail, 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 (Changes/Update) plus the resource (a Caliper eval) and enumerates exactly which attributes are mutable (title, description, visibility, schedule, runOnPublish, regressionThreshold). The immutable-field callout sharpens the boundary versus caliper_evals_create.

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 explicit when-to-use rules ('Pass only what changes') and an explicit alternative with condition ('The dataset, rubric snapshot, and target are fixed at creation — create a new eval to change those'). It also instructs the agent to surface credit spend when enabling scheduled/on-publish runs.

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