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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and closed-world, so the safety profile is fully covered. The description adds nothing beyond that - no behavior on a missing/invalid ID, no note on what the value payload contains.

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?

A single front-loaded sentence with zero filler. It is appropriately sized, though its brevity leaves little room for the usage context an agent would benefit from.

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 single-parameter read with full annotation coverage, the minimal description is nearly adequate. However, with no output schema, the agent gets no hint about what a 'custom field value' object returns, leaving a small but real gap.

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?

Only one parameter (id, uuid) and schema description coverage is 100%, so the schema already documents it. The description's 'by ID' merely restates the parameter without adding format or lookup 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 (Get) and resource (custom field value), which distinguishes it from get_custom_field_definition and list_custom_field_values. It does not, however, explicitly contrast itself with the many sibling get_* tools or explain the definition/value relationship.

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?

No guidance on when to use this versus list_custom_field_values (to find values) or get_custom_field_definition (for the schema/definition). No prerequisites or context about retrieving a value by ID are given.

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