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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds value by disclosing the response payload (size, block size, state, attached instance, encryption, labels, snapshots), which matters given there is no output schema. It omits auth/permission context, but the read semantics are clear.

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 compact sentences, front-loaded with the resource and its returned fields, ending with the endpoint. No wasted words.

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 and no nested objects, the field enumeration usefully tells the agent what a call returns. Parameter and safety information is already covered by schema and annotations, leaving only minor gaps such as error behavior for invalid ids.

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 coverage is 100% with only two parameters, both fully documented in the schema (id pattern, zone enum and default). The description adds no parameter-level meaning, so the baseline 3 is appropriate.

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 details) and resource (one block storage volume), then enumerates the fields returned and cites the underlying endpoint. The singular 'one' cleanly distinguishes it from the sibling exoscale_list_block_storage_volumes.

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 a single-resource lookup by id, which contrasts implicitly with the list sibling, but it never explicitly says when to use this versus exoscale_list_block_storage_volumes or states any prerequisite (e.g., needing a known id). Usage is inferable rather than spelled out.

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