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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context: the breadth of the returned record and the guarantee that schemas remain readable for paused or retired capabilities. It stops short of noting not-found behavior or any cost/latency of assembling comparable prices and clearing data.

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 sentences, front-loaded with the action and scope; the long field enumeration is justified because no output schema exists to describe the return. Slightly list-heavy, but no wasted 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 carries the return-value burden and does so thoroughly, and the read-only annotations cover the safety profile. Minor gaps: behavior on unknown or unauthorized ids, and whether the extensive history/comparable-price data is always returned or conditional.

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%, so both parameters are already documented, including the optional agent_key and its effect on owned repair notices. The description only echoes 'by id' for capability_id and adds nothing about agent_key. Baseline 3 is appropriate when the schema carries the semantics.

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 ('Read one capability by id') and then enumerates exactly what the payload contains: schemas, price, SLA, verification/repair history, uptime, freshness, maintenance status, ownership periods, comparable prices, clearing data. This clearly separates it from capabilities_list (enumeration), capability_call (execution) and capability_call_get (a specific call record).

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?

Usage is implied rather than prescribed: 'Schemas stay readable when calls are paused or retired' hints that this is the tool to inspect a capability even when it is unavailable. But no sibling is named as an alternative and there is no explicit when-not-to-use guidance (e.g. versus capabilities_list for discovery).

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