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

Annotations only cover the safety profile (readOnly=false, idempotent=true, destructive=false, openWorld=false); the description adds the genuinely useful traits: partial-update semantics (omitted fields kept, "" or [] clears), automatic reactivation of a paused plan, no quota, the returned payload including this week's progress, and the error contract (invalid_payload: <field>: <problem>).

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, then update semantics, then return/error behavior — each clause does work. It is dense with parenthetical detail, which makes it slightly harder to scan, but nothing is redundant 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 single-input mutation tool with an output schema, the description covers everything an agent needs: what it writes, how partial updates and clearing behave, the paused-plan side effect, quota absence, and the error shape. Return values need not be explained since an output schema exists.

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?

Reported schema description coverage is 0% at the top level (only the wrapping 'input' object), and the schema is nested, so the description has to carry weight. It does: it names each meaningful input (goal in their own words, target roles, applications a week, review day) and explains the clear-value convention. It stops short of restating the per-field constraints (max 5 roles, 1–50 range) that the nested schema does define.

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+resource ('Save the weekly job-search plan the user chose') and enumerates the fields it covers (goal, target roles, applications per week, review day). Combined with the create-or-overwrite semantics, an agent can separate it cleanly from get_coach_plan and pause_coach_plan without opening 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?

Gives clear operating context: use it when the user has chosen a plan, it creates or overwrites only the supplied fields, and it reactivates a paused plan. It does not explicitly name the read counterpart (get_coach_plan) or pause_coach_plan as alternatives, so there are no stated exclusions — clear context but no routing guidance.

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