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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The description adds the underlying API mapping (GET /counterparties/{id}), which is useful for an API-wrapper suite but discloses nothing about error behavior (e.g. missing id) or response shape.

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, with no wasted prose. The endpoint line is marginally redundant but is consistent with the API-mapping style of the surrounding toolset.

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 one-parameter read tool whose annotation already declares readOnly, the description plus schema is essentially sufficient. Only minor gaps remain, such as what a counterparty object contains or what happens on an invalid id.

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?

With 100% schema description coverage on a single required 'id' parameter, the schema already carries the parameter semantics. The description only restates that lookup is by id, adding no format or sourcing detail.

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 ('Get a single counterparty by id'), which cleanly separates it from list_counterparties. It does not explicitly name the sibling it is not, but the singular scoping makes the distinction inferable.

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 gives no when-to-use or when-not-to-use guidance and does not point to list_counterparties as the way to discover ids. The 'by id' phrasing weakly implies a prerequisite lookup step, but nothing is stated.

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