checkpoint

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, so the mutation profile is covered; the description adds 'all saved atomically,' which is genuine behavioral context. It does not explain what happens to prior checkpoints/sections when repeated calls are made (append vs replace), which is the main open behavior for a non-idempotent write.

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 front-loaded sentences with no filler; the content list comes first, then triggers, then the size/speed rationale. Slight density in the first sentence (three clauses plus 'atomically') but nothing to cut.

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?

An output schema exists so return values need no explanation, and cadence, triggers, and required content are all covered. What is missing is the relationship between repeated checkpoints and existing state, which matters for a non-idempotent session-scoped save.

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?

The description names the required payload fields (summary, where stopped, next action) and gestures at 'knowledge items and state changes,' but with 70% schema coverage and 10 parameters it leaves the tasks array, the fixed section keys, session_label, and client unmentioned. Adequate but not compensating for the remaining documented gap.

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 pair ('Save a checkpoint of this working session') and enumerates what the checkpoint contains: summary, stopped position, next action, plus optional knowledge items and state changes. It is clear what the tool does, but it never distinguishes itself from siblings such as prepare_handoff or remember/update_state, which an agent must choose between.

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 concrete cadence ('every ~20-30 minutes or 8-10 substantial exchanges'), hard trigger conditions ('IMMEDIATELY when the user mentions limits, switching accounts/apps or ending the session'), and a conditional delegation ('whenever checkpoint_status recommends it'). It even resolves the completeness trade-off with 'an early checkpoint beats a late, complete export.'

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