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

Beyond the readOnly/idempotent/openWorld annotations, the description discloses the freshness model (fresh/stale/partial/unavailable), what is included (signed coverage, source cursor, issue/expiry times), and real operational constraints — the archive is process-local, capped at 128 documents, one hour, and lost at restart. That is material context an agent would otherwise discover only by failing.

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 scope in the first sentence and the retrieval mode plus limits last; no filler. It is telegraphic and dense, but every clause conveys distinct 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?

There is no output schema, yet the description enumerates what comes back (signed coverage, source cursor, issue/expiry times, observation status) and what explicitly does not. Combined with the archive limits and the single optional parameter, an agent has everything needed 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 coverage is 0%, so the description must carry the lone parameter, and it does: content_hash 'retrieves an exact retained document', with the retention limits given so the agent knows the hash may no longer resolve. The hash syntax itself is documented by the schema pattern, so no duplication is needed.

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 ('Attest observed native fetchhub-4 gas, transactions and blocks') plus a precise scope ('latest available finalized hour, four 15-minute windows'). The exclusion clause ('No Ethereum data, native security verdict, anomaly assessment or live chain RPC') implicitly separates it from security_report and network_status, but no sibling is named outright.

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?

Exclusions hint at when this tool is the wrong choice, and the coverage/status framing implies its role, but there is no explicit 'use verify_network_state_attestation to check the signature' or 'use network_status for live chain data'. The agent must infer the routing from the sibling names alone.

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