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

Annotations already declare readOnlyHint, idempotentHint, and closed-world, so safety is covered. The description adds meaningful context beyond them: the data is 'immutable'/'canonical' and explicitly excludes changing ledger metrics, and metadata is 'claim-status-separated', which tells the agent this is static identity data rather than live state.

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?

Two dense sentences, front-loaded with the primary return content and followed by a scoping exclusion. Every clause carries information; 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?

With no output schema, the description must describe the return payload, and it does so concretely (identity fields plus project metadata, with a stated exclusion). For a zero-param, read-only tool with full annotation coverage, nothing an agent needs 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the 4 baseline applies. No parameter guidance is needed or missing.

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 ('Returns') and resource ('immutable canonical ASTEROID identity') and enumerates the returned fields (network, issuer, 160-bit currency code, token identifier). It implicitly distinguishes itself from metric/state siblings like get_market_state and get_token_stats by emphasizing immutability, but never names a sibling explicitly.

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 phrase 'No changing ledger metrics' hints at when-not to use this tool (i.e., for live metrics reach for the state/stats siblings), but there is no explicit when-to-use statement or named alternative. Usage is only implied.

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