List Groups

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

Adds behavior beyond the annotations: a dual data source with a degraded fallback ("falls back to the local desktop database (without group_id)"), which is correctness-critical since the group_id may be absent. The safety profile is only restated from annotations ("Read-only with no side effects") and there is no mention of latency, rate limits, or whether the fallback is surfaced in the result, keeping it short of 5.

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?

Front-loaded with the resource and return fields, then source caveat, then routing guidance — a sensible information hierarchy with no filler. The "Read-only with no side effects" sentence largely duplicates the annotations and could be dropped.

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?

An output schema exists, so return values need no explanation, yet the description still names the key fields and their ordering. Combined with the fallback caveat and the sibling routing note, an agent has everything needed to call this correctly.

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%, with both limit (range 1-200, default 50) and query (case-insensitive substring, empty returns all) fully documented in the schema. The description says nothing extra about filtering or pagination, so it meets but does not exceed the baseline for a fully documented schema.

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 ("List Signal groups") and enumerates the returned fields (group_id, name, description, members, admin lists) plus the sort order. It also explicitly distinguishes itself from list_chats, so an agent can pick between them without opening either schema.

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?

Gives a concrete downstream use ("obtain group_id values needed by send_message") and names the alternative with the condition that selects it ("Use list_chats instead for a combined view of both direct and group chats"). Both when-to-use and when-to-use-something-else are covered.

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