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

Annotations already declare readOnlyHint=true and destructiveHint=false, lowering the bar. The description adds genuinely useful behavioral context beyond that: the listing is all-inclusive ("every guide") and the roll-up explicitly includes guides homed to a property with no rendering surface — an edge case an agent might otherwise assume is excluded. No contradiction with the annotations.

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?

A single well-crafted sentence of roughly 30 words. It front-loads the verb and resource, then packs only informative detail: the field enumeration and the no-rendering-surface edge case in the parenthetical. Every word earns its place with no filler or redundancy.

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?

For a 13-filter list tool, the description establishes the scope and key output contents, and the output schema plus 100%-covered parameter descriptions carry the rest. It does not explicitly state the default unfiltered behavior or distinguish the compact/full row shapes, but those details are documented in the schema, leaving only a minor gap.

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 100% across all 13 parameters, so the baseline of 3 applies. The description adds no per-parameter meaning — it only establishes global scope and output contents — but it doesn't need to, because each parameter already carries a detailed explanation in 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?

The description states a specific verb and resource — "List the bicycle.guide registry" — and enumerates exactly what is returned: home, status, access, standard, syndication, grounding, plus a distribution roll-up. The plural registry-wide scope distinguishes it from the singular get_guide, and the "guide registry" resource clearly separates it from list_capabilities and list_taxonomy.

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 implies its use case — whenever a complete registry view with all fields and the roll-up is needed — but it never names siblings or states when to prefer get_guide, list_capabilities, or list_taxonomy. No exclusions or alternative conditions are given, so routing guidance must be inferred from the differing resource types.

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