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

The description goes well beyond the readOnly/idempotent annotations by disclosing concrete behaviors: re-verifying the board signature against pinned did:web:csoai.org#board-attestation-1, never calling PENDING attested, and defining NOT_PUBLISHED and UNREACHABLE fallback states. This gives an agent accurate expectations for the operation's result semantics. No contradiction with the readOnlyHint=true annotation.

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?

The description is a single dense run-on sentence with a long colon-delimited enumeration, making it structurally unwieldy despite containing no wasted words. Front-loading the verb and resource is good, but the content would be more digestible as shorter sentences or bullet points.

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?

Given the presence of an output schema that presumably defines return fields, the description covers the source URL, the read scope, verification behavior, semantic limitations, and edge-case states. An agent has enough information to decide whether to call this tool and what to expect, with nothing substantial missing.

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?

The tool has zero parameters and schema coverage is trivially 100%, so the baseline of 4 applies. The description adds context about the fixed source URL and the verification performed, which substitutes for parameter-level guidance since no parameters exist to document.

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?

The description opens with a specific verb and resource: 'Read the latest signed measurement-capsule index published at https://councilof.ai/measurement-capsules/latest.json'. It enumerates the precise contents read (index root, batch fields, board signature re-verification, anchor states), which clearly distinguishes it from sibling verification tools that target individual capsules or cards.

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 description provides strong contextual scope, such as 'States only: measurement, not endorsement; no verdict, score or ranking' and the NOT_PUBLISHED/UNREACHABLE conditions, which help an agent infer when the tool is appropriate. However, it never names sibling tools or explicit when-to-use/when-not-to-use conditions like 'use verify_capsule instead for a single capsule'. Usage is implied by scope rather than stated directly.

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