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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and non-open-world, so the safety profile is fully covered. The description adds only that lookup accepts either an ID or a key; it says nothing about missing-value behavior or error semantics, which is the main remaining unknown for a getter.

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?

One short sentence, front-loaded with the verb and resource, with zero filler. Appropriately sized for a one-parameter getter, though extremely minimal.

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 simple read-only single-record lookup with full schema coverage and annotations, this is minimally sufficient. What an agent cannot infer is what happens on a nonexistent or ambiguous identifier, and there is no output schema to fall back on.

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% and the single parameter already documents "(gv_xxx) or key." The description's "by ID or key" restates the schema rather than adding format or fallback detail, so baseline 3 applies.

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 (retrieve a global value) and scope (one, by ID or key), which separates it from list-global-values by singular vs plural. It does not explicitly name the sibling, so it stops short of a 5.

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?

"Retrieve one" implies the single-record use case versus the list tool, but the description never states when to use this rather than list-global-values or what to do if the identifier is unknown. Usage is implied rather than stated.

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