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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuinely non-structured context: the meaning of the support field enumerations and the important caveat that reminder_only means AccountsOS does not produce the form.

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?

Two sentences, front-loaded with the purpose, no filler. The second sentence is dense with field semantics but every clause (support values, support_note, reminder_only caveat) earns its place.

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 usefully explains the returned fields' semantics and the reminder_only distinction, which is what an agent needs to interpret results. Only gap is the lack of a defined 'upcoming' window and no mention of defaults for include_completed.

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 both company and include_completed are fully documented in the schema. The description adds nothing about either parameter, so the baseline 3 applies; when output schema is absent it also does not state whether 'upcoming' has a default horizon.

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: 'Get upcoming tax and filing deadlines.' That is clear enough to act on, but it never distinguishes itself from related siblings such as get_vat_periods, get_tasks, or get_gov_guidance, which also surface tax/filing time information.

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?

Usage is only implied by the phrase 'upcoming tax and filing deadlines'; there is no statement of when to choose this over get_vat_periods or get_tasks, and no prerequisites or exclusions. The include_completed toggle hints at scope but the description does not elaborate.

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