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

readOnlyHint=true already tells the agent this is a safe read. The description's one contribution beyond annotations is that the result nests the company's people, which is genuinely useful for planning the call. It says nothing about error behavior for invalid ids or about the depth of the embedded people data.

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 short sentence with zero filler, front-loading the action and resource. Nothing redundant or padded.

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?

Adequate for a one-param read tool with full schema coverage and a readOnly annotation. With no output schema, however, the description only hints at the return shape ("with its people") and leaves the rest of the payload undocumented.

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 one required parameter and 100% schema description coverage, the schema already carries the id semantics including its source (papierkram_list_companies) and accepted integer/string forms. The description adds no format or constraint detail beyond that, 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 ("Get one contact (company) by id") and adds the scope detail that the related people are included. It is clearly distinguishable from papierkram_list_companies and papierkram_get_person, though it never names those siblings explicitly.

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: fetch a single company when you already have its id (the schema notes the id comes from papierkram_list_companies). There is no explicit statement of when to prefer this over listing companies or fetching a person instead.

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