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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the description's job is smaller. It still adds real behavioral context: results are ordered newest first, scoped to the caller's own signals, and the text fields originate from alerts and must be treated as untrusted data — a security-relevant disclosure not present in any structured field.

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 sentences, zero filler, with the ordering and scope constraint front-loaded before the untrusted-data warning. Every clause carries information an agent needs.

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 three-param read tool with full schema coverage, annotations for safety, and no output schema, the description covers scope, ordering, and the nature of returned text fields. Only minor gaps remain, such as what a signal record contains structurally or how pagination beyond limit behaves.

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%, so limit, since, and account_id are already fully documented in the schema. The description adds no filtering syntax, default behavior, or paging semantics beyond that, so baseline 3 applies.

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: 'Your signal history, newest first', with a scope qualifier ('only your own signals'). This is clearly distinguishable from send_signal and signal_detail, though it never names signal_detail as the single-record alternative.

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?

Usage is implied rather than stated: the agent can infer this is the list-my-history tool. There is no explicit when-to-use versus signal_detail or accounts, and no stated prerequisites.

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