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

Annotations cover the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false, openWorldHint=true); the description adds real context beyond them: no account or key required, one call, the filing is published to payers, and gaps are permitted. It does not say what happens on re-filing — whether a second attestation replaces or coexists with the first — which matters given idempotentHint=true.

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-loaded with the identity of the tool and its sibling contrast, then workflow and preconditions. Every sentence carries a distinct instruction; 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?

Covers purpose, prerequisites, authorization, and the gap-tolerance policy for a 5-parameter write tool with a nested object. The one gap is the absence of an output schema combined with no description of what the filing returns (an id, a link, a verification status), which an agent may want to confirm success.

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%, so baseline is 3; the description still adds meaning by tying 'answers: false' to the gapPlan field and directing the agent to baseline_controls for control ids. It gives no hints on the shape of the answers map beyond what the schema already documents.

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 ('file your operator's control-baseline attestation') and immediately positions it against the sibling counterparty_control_baseline by contrasting whose controls are published. An agent can pick between the two without opening either 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?

Gives explicit sequencing ('get the control ids from the baseline list first'), an authorization precondition ('only file for a party you are actually authorised to speak for'), and the when-to-use rationale (payers see it before settling). It also covers the awkward case of partial compliance rather than leaving it ambiguous.

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