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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds real value beyond that: it states the contacts are from a 'shared phone-book' (shared scope), enumerates the returned fields in lieu of an output schema, and identifies the underlying endpoint GET /contacts. It does not discuss pagination behavior or result limits.

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?

Three compact sentences with the purpose front-loaded, followed by filter capabilities and the endpoint. There is little waste, though the trailing 'GET /contacts' is a marginal detail and the filter summary slightly duplicates what the schema already conveys.

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?

With 16 optional parameters, no output schema and solid annotation coverage, the description does the needed work by enumerating return fields and framing the tool as a filtered list over a shared phone book. Pagination semantics are left to the schema's page/per_page descriptions, which is a minor gap but not a blocker.

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 schema already documents all 16 parameters in detail, and the description only summarizes the filterable fields (name, company, email, number, update time). It omits several parameters entirely (blocked, speeddial, page, per_page, the *_work variants) and its note on search_number largely repeats the schema text. Baseline 3 is 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 opens with a specific verb and resource ('List the shared phone-book contacts') and enumerates what each record contains (names, company, numbers, emails, tags, blocked flag), which tells an agent exactly what it gets back. It stops short of naming sibling tools like placetel_get_contact or placetel_create_contact, so the read-vs-single-record distinction is only implied.

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?

'Filter by name, company, email, number or update time' plus 'search_number finds a contact by any of its numbers' gives implied usage context for lookup scenarios. However, there is no explicit when-to-use guidance, no exclusions, and no pointer to the sibling tools (get_contact, create_contact, update_contact) that an agent would otherwise have to disambiguate from names alone.

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