history_session_checkpoint

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

Beyond the annotations (idempotentHint, readOnlyHint=false, destructiveHint=false), the description discloses archive rotation behavior ('archives that exceed MCP_HISTORY_MAX_LINES/BYTES soft-rotate to the next N.md before append') and that content is redacted. 'Redacted' is asserted but not defined, and no auth/permission requirements are covered, so it is not a 5.

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 dense sentences with the core action front-loaded and zero filler. The rotation detail is compact, though the MCP_HISTORY_MAX_LINES/BYTES and 'N.md' shorthand assumes environment knowledge.

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 write tool with 17 parameters, no output schema and no per-parameter schema docs, the description leaves most of the call surface unexplained. It covers the bootstrap-to-checkpoint flow and rotation, but an agent still cannot know what most fields should contain.

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 0% and 17 parameters exist, so the description must carry the semantic load. It only explains three (session_key, expected_path, raw_user_input), leaving 14 parameters such as findings, decisions, next_actions, files_changed and turn_id completely undocumented anywhere.

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: 'Append an idempotent, redacted development checkpoint.' An agent knows this writes a checkpoint entry. It does not explicitly contrast with the closely related siblings (history_session_read, history_session_search, history_session_validate), so it falls short of full sibling differentiation.

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 routing context: pass session_key and expected_path 'exactly as returned by history_session_bootstrap', which tells the agent this tool belongs after bootstrap. It also specifies raw_user_input must be verbatim. No explicit when-not-to-use or exclusion is stated.

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