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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description usefully adds the data returned (quantity, cost, location, custom fields) and names the underlying GET endpoint, though it says nothing about behavior when the id is not found.

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 are front-loaded with the core purpose and returned fields. The 'GET /parts/{id}' sentence is mildly redundant with the annotations and title but does not obstruct the description.

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 tool with annotations covering safety and no output schema, the description supplies the returned field list that would otherwise be missing. Only edge-case behavior (e.g., unknown id) is left unaddressed, which is minor for this complexity level.

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%, including an example id format, so the schema already fully documents the single part_id parameter. The description's 'by id' adds no syntax or format detail beyond that, making the baseline 3 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?

The description states a specific verb and resource ('One part by id') and implicitly distinguishes itself from upkeep_list_parts by scoping to a single id. It does not explicitly name sibling alternatives, so it stops short of the top score.

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?

Usage is only implied: 'by id' suggests it is the tool to call when the part id is already known, but the description never says when to prefer it over upkeep_list_parts or upkeep_update_part_quantity. No exclusions or alternatives are stated.

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