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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds real behavior beyond that: the response envelope shape ({oncalls:[...]}), the per-record fields (id, name, timezone, layers), and the team scoping of the endpoint — all useful for planning subsequent calls.

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?

Compact and front-loaded — purpose first, then return shape, then chaining guidance, then endpoint. The inline '{oncalls:[...]}' is slightly cryptic but earns its place by conveying the response wrapper.

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 no output schema, the description compensates by sketching the return shape and fields, and it names the id-consumer tools. For a single-optional-param read tool, this is close to complete; only deeper pagination/size behavior is unstated.

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% and the single teamId parameter is fully documented in the schema, so baseline is 3. The description only echoes team scoping ('team-scoped') without adding format or default-resolution detail beyond what the schema already provides.

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 a team's on-call schedules') and scopes it to a team. The mention of the underlying endpoint GET /on-calls and the id-based follow-ups clearly separates it from spike_get_on_call and spike_who_is_on_call_next.

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?

Explicitly tells the agent what to do with the returned id ('Use the id with spike_get_on_call / spike_who_is_on_call_next'), which routes workflow correctly. It does not state when-not to use it or contrast with sibling list tools (e.g. spike_list_teams), so it stops short of a full 5.

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