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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely useful behavior: no side effects ('never triggers a scan') and error behavior ('a missing read says so'). It does not discuss auth requirements, rate limits, or failure modes beyond the missing-read case.

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?

Three dense sentences, front-loaded with the id-source constraint, then return shapes, then side-effect/error guarantees. No filler and every clause carries information an agent needs.

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 compensates by describing the return payloads for both id families (stored read text + citation + as-of time; lesson text + optional transcript). Combined with the annotation coverage and the missing-read note, nothing essential is missing for correct invocation.

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 description coverage is 0% and the single 'id' parameter has no schema-level documentation, so the description carries the full burden — and it does, spelling out the three id namespaces and their value formats (address, mint, slug). This is meaning that cannot be recovered from the schema.

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 (fetch) and resource (one result) and immediately ties it to the sibling 'search' as the id source, with concrete id formats (rh:<address>, sol:<mint>, learn:<slug>). An agent can distinguish this from search and from the rh_* scan/detail tools without opening the 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?

The description says the id must come from search and that the call 'never triggers a scan', which implicitly routes scanning to a different tool (rh_scan_now). It gives clear context for use but does not name the alternative tool explicitly or state when-not-to-use beyond the scan note.

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