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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine context beyond that: source endpoint, 'Canton-only, cached snapshot (captured_at)', and the flagging behavior when upstream stops publishing rewards. Return format detail is limited but the caching semantics are a real addition.

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 verb and source, then the field list. The enumeration of covered fields is long but each item earns its place given there is no output schema to fall back on. No filler sentences.

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, the description has to describe what comes back, and it does so thoroughly: SV list/count, voting threshold, sequencer count, latest mining round, featured-apps count, rewards in CC with closed round and date, plus caveats about stopped publishing and caching. Nothing an agent needs to call it correctly is 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?

Zero parameters, so the schema has nothing to document and the description carries no burden here; baseline 4 applies. The description does not need to explain parameter usage because no parameters exist.

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+resource ('Get the latest Canton Network ON-CHAIN state snapshot from the public Scan API'), enumerates the exact contents it returns, and names two siblings it is not. An agent can distinguish it from get_network_stats and get_token_market without opening any 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 exclusions with named alternatives ('NOT CCPEDIA content counts (get_network_stats) and NOT price/TVL (get_token_market)') and frames the use case as 'live network telemetry.' The positive trigger is implied rather than stated, so a 4 rather than a full 5.

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