Entity timeline

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

No annotations exist, so the description carries the full burden. It does disclose return composition well (each value change with what it replaced and when it stopped holding, merged with dated passages), which is genuinely useful. However, it says nothing about authorization, result size limits, pagination, or ordering guarantees for a tool that could return a large merged history.

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 core purpose, then examples, then the anti-pattern guidance — a logical order with little waste. The single long sentence with em-dash parentheticals is dense, slightly reducing readability.

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 what the return contains and how the two sources merge. Date scoping lives in the schema. Adequate for a 3-param read tool, though limits/pagination on the merged result remain unaddressed.

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 since/until/subject are already documented in the schema. The description's mention of 'content-dated passages' hints at temporal semantics but adds no syntax or format detail beyond the schema's ISO-date notes. 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?

States a specific verb+resource ('Chronological history of an entity') and precisely defines the two merged data sources (bitemporal fact-store value changes plus content-dated passages). It is clearly distinguishable from siblings like lore_query_facts and lore_search.

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?

Explicitly frames the trigger questions ('what happened to X', 'history of X') and names the naive alternatives to avoid — repeated as-of fact queries and windowed searches. This routes the agent away from lore_query_facts/lore_search with a stated condition.

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