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

With no annotations, the description carries the transparency burden. It discloses that results are paginated, which is a behavioral trait not explicit in the schema. However, it does not mention default filtering of archived/deleted contacts or any access limitations, leaving significant gaps.

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?

The description is extremely concise—two sentences with all words earning their place. It front-loads the primary action and includes the most relevant behavioral detail (pagination) without redundancy.

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 list tool with 10 parameters and no output schema, the description covers the essential behavior: listing contacts with filters and paginated results. The schema fills in all parameter details, and the tool's purpose is unambiguous. It could mention default sort order or that soft-deleted contacts are excluded by default, but those are in the schema already.

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%, so the baseline is 3. The description lists several filter fields (status, favorite, company, tag, search) but adds little beyond the schema's own parameter descriptions. The pagination mention provides context, but not parameter-level syntax.

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 clearly states 'List contacts' with a specific verb and resource, and mentions optional filters and pagination. This distinguishes it from single-record tools like contact_get and other list tools like note_list, though it does not explicitly name alternatives.

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 is provided about when to use this tool versus alternatives such as contact_get or contacts_needing_attention. The description only describes the function without exclusions, prerequisites, or recommended contexts.

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