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

The description adds one genuinely useful behavioral fact beyond the annotations: the call is 'Free', a cost signal absent from the structured fields and relevant given the sibling list_pricing. It does not, however, describe error behavior for unknown or non-public IDs. Note the mismatch between the 'get/describe' framing and readOnlyHint=false, though this is an annotation oddity rather than a direct contradiction.

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 short sentences, front-loaded with the action and target; nothing is wasted. The trailing 'Free.' is slightly clipped in tone but does carry information, so the brevity is mostly earned rather than merely terse.

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?

An output schema exists, so return values need not be described. However, for a lookup tool the critical missing piece is where a valid capability_id comes from and how it relates to list_capabilities, which the description never supplies.

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 required parameter capability_id gets no explanation in the description — no format, no example, no pointer to where IDs come from (e.g. list_capabilities). With one undocumented parameter, the description fails to compensate for the coverage gap.

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 ('Describe') and a specific resource ('one stable public AIOS capability ID'), which clearly distinguishes a single-ID lookup from the sibling list_capabilities. The qualifiers 'stable' and 'public' also narrow the scope of what IDs are valid, though the sibling distinction is left implicit rather than named.

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?

'one ... capability ID' implies this is the single-item lookup in contrast to list_capabilities, but the description never says when to prefer this over the list tool, nor what to do if the ID is unknown. Usage is inferable from the phrasing rather than stated.

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