add_blockout

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the write/safety profile is largely covered. The description adds genuinely non-obvious behavioral detail about timezone handling ('no offset means church time') and defaulting rules, but says nothing about what happens on overlapping/duplicate blockouts, whether the blockout is visible to others, or error conditions.

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-loads the one-line purpose, then a dense but waste-free parameter block. Every sentence earns its place, though the telegraphic clause stacking ('repeat with every=N repeats every N periods; monthly_by picks...') is harder to parse than it needs to be.

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 7-parameter mutation tool with no output schema and zero schema documentation, the description covers formats well but is silent on the return/confirmation, error behavior, whether the new blockout replaces or coexists with existing ones, and the `reason` field. Adequate but with clear gaps.

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?

With 0% schema description coverage the description must carry parameter meaning and it mostly does: start/end formats (date vs ISO datetime), end-required-for-datetimes, offset-less = church time, every=N repetition, monthly_by day_of_month vs Nth week, repeat_until as a date. The `reason` parameter is never mentioned, leaving one of seven parameters undocumented in both schema and description.

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?

Specific verb ('Add') plus resource ('blockout') with the operational effect stated ('so you aren't scheduled'). It is trivially distinguishable from remove_blockout, list_blockouts and skip_blockout_date by name, but the description never names or contrasts those siblings explicitly.

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?

The phrase 'so you aren't scheduled' implies the use case (marking personal unavailability), which is enough context to pick this over my_schedule. However there is no guidance on when to prefer skip_blockout_date vs remove_blockout, no mention of prerequisites, permissions, or conflict behavior.

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