history_read

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint, so the safety profile is covered. The description adds meaningful behavior beyond annotations: events are returned complete, in snapshot order, and with pagination. It does not discuss errors or rate limits, but the added context is sufficient for this simple read operation.

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?

One compact sentence with no filler. It front-loads the verb and resource, then efficiently packs completeness, ordering, and pagination. Every phrase earns its place.

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 simple read-only paginated fetch with an output schema and comprehensive annotations, nothing critical is missing: session ID, record completeness, ordering, and pagination are all explicitly present. The tool's complexity is low, and the definition covers the full call contract.

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%, so the description must compensate. It covers session_id ('opaque session ID') and pagination (limit/cursor), giving high-level semantics for the parameters. However, it leaves details unstated, such as whether the cursor itself is opaque or how limit interacts with pagination. The schema's defaults and titles fill in some meaning, so the description is adequate but not exhaustive.

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 ('Read'), a clear resource ('complete events'), and the key differentiator ('by opaque session ID'), plus ordering and pagination. This distinguishes it from siblings like history_list and history_search, which imply broader listing or searching rather than a direct session-based read.

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?

The description gives clear context for when to use the tool: when you have a session ID and need the full event sequence in snapshot order. It does not explicitly name alternatives or exclusions, but the intended use case is evident from the wording and sibling names.

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