Count logs

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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description's only added behavioral claim is 'Cheap', which is a genuine cost signal not present in the structured fields, but it says nothing about count caps, accuracy limits, or whether the count is bounded.

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 sentences with zero filler, and the returned value is front-loaded ahead of the cost hint. Every clause carries information.

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 parameter-rich but conceptually simple read tool with a full-coverage schema, a complete annotation safety profile and a stated return value, the description is adequate. It omits only what to do with the count or how it compares to the histogram, which is a minor gap.

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% across all six parameters, so query syntax, range formats, streams, instance and the from_time-overrides-range rule are all documented in the schema. The description adds no parameter detail, so the baseline of 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 and resource: returns the exact number of messages matching a query. The word 'Exact' usefully contrasts with the histogram sibling, but no sibling is named, so an agent still has to infer the boundary with log_histogram or search_logs.

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?

'use it to size a problem' implies a usage pattern (cheap pre-flight sizing before heavier queries) but gives no explicit when-not guidance and never names the alternatives (search_logs, log_histogram) that an agent should pick when it needs the messages themselves rather than a tally.

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