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

Goes well beyond the destructiveHint annotation by spelling out the upsert semantics: re-scheduling the same notebook replaces the timetable and recipients, omitting emails clears recipients, and a disabled schedule is re-enabled. It also discloses compute consumption, failure email/in-app notification, and that owners/admins/editors may schedule.

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 purpose and the sibling routing, then behavior, then return shape — a sensible order. It is dense and slightly run-on (multiple clauses per sentence), but nearly every clause carries operational information rather than padding.

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 mutating, permission-gated scheduling tool with no output schema, the description covers permission requirements, cadence limits, replacement behavior, notification behavior, and even enumerates the return fields. An agent has everything needed to call it correctly and predict the consequences.

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 coverage is 100%, so the schema already carries the baseline, but the description adds real meaning: the cadence floor ('at most once an hour'), the timezone the cadence is read in, and the destructive consequence of omitting emails on a repeat call. That last point is not derivable from the schema alone.

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 precise verb and resource ('Run every cell of a notebook on a timetable') and immediately distinguishes itself from the two nearest siblings, fastero_run_notebook (one-off) and fastero_set_python_schedule (Python project scripts). An agent can pick the right tool without opening any 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?

Explicitly routes to alternatives with conditions attached ('to run it once now, fastero_run_notebook'; 'for a Python project's script, fastero_set_python_schedule'; 'fastero_set_schedule_enabled switches it off'). It also states the permission gate — owners, admins and editors of the project.

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