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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false. The description adds one behavioral detail consistent with those annotations — reusing the session_id updates a single row (upsert) — but says nothing about what gets overwritten, permission needs, or the effect of omitting session_id.

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 short, front-loaded sentences with no padding, so it is not verbose. But the brevity is under-specification rather than economical conciseness — the sentences carry usage timing while omitting the tool's purpose entirely.

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 16-parameter persistence tool with many siblings performing similar saves, the description omits what a checkpoint is, what the context field should contain beyond the bare schema hint, and how it relates to palim_resume/palim_save_context. Output-schema coverage excuses return-value explanation, but the write-side guidance is still thin.

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 description coverage is 100% and the schema already documents all 16 parameters, including the session_id reuse convention. The description's only parameter remark ('reuse claude-code-<client session id>') repeats what the schema already states, so it adds no meaning beyond structured fields. Baseline 3 is appropriate.

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?

The description never states what the tool does — it only says when to call it ('after connecting AND again after each meaningful chunk of work'). An agent must infer from the name/title that this writes a checkpoint record. It does not distinguish the tool from its near-identical siblings palim_save_context, palim_save_session, or palim_add_memory.

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?

It gives concrete timing ('after connecting AND again after each meaningful chunk of work'), which is genuine when-to-use guidance. However, it names no alternatives and provides no when-not to use it, leaving the agent unable to choose between this and palim_save_context/palim_save_session.

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