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

Annotations already cover readOnly, idempotent, non-destructive and closed-world. The description adds genuinely new behavioral context — it reads only the *public* view and never returns email addresses or private details, which materially affects how an agent should present results and what it may promise the user. No error or invalid-link behavior is described, so 4.

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 tight sentences: what it reads, when to use it, what it deliberately does not expose. No hedging, no repetition, and the core purpose is front-loaded.

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 an output schema present, the description need not spell out return structures, and it still gives a useful gist (open/full slots, poll answers per option, signer counts). Combined with 100% schema coverage and full annotations, an agent has everything needed; only handling of invalid or non-public links is unaddressed.

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% and the share_url property already documents the link format and the bare 8-character id fallback. The description's "Takes the public share link (signupsheet.page/s/…)" largely restates that, adding only the word 'public'. Baseline 3 is appropriate when the schema does the heavy lifting.

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 ('Reads') and resource ('public status of a SignUpSheet.page sign-up sheet, date poll or group card'), and enumerates the three variants that map onto the create_* siblings. An agent can immediately tell this is the read counterpart to the creation tools without inspecting the 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?

"Use it when the user asks how their sheet, poll or card is going" gives a clear selection trigger, and the public-share-link constraint narrows the context further. It stops short of stating when not to use it (e.g., private/owner views or non-existent links), so 4 rather than 5.

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