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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description goes further by disclosing that only *retained* logs are counted (retention window affects results), that the default window is 24h, that from/to is a half-open [from,to) interval, and that counts are log rows rather than request totals. It does not discuss what happens for an inaccessible or unknown project, or any limits on result cardinality.

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?

Four dense sentences, front-loaded with the verb and scope, and the 'not request totals or runtime health' disambiguation earns its place. The opening sentence is long and packs the return fields and the time-window options together, which slightly reduces scannability, but there is no filler.

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?

There is no output schema, yet the description enumerates what comes back (counts by level, category, asset type, status class; newest/oldest observation; p95 latency), which is exactly the burden it must carry. Combined with the time-window rules and the retention caveat, an agent has enough to call it correctly and interpret the result for this read-only aggregation tool.

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 carries the full burden and does add real meaning: timeRange has a stated default (24h), from/to are described as an alternative exact window with half-open semantics, and level/category are explained as narrowing filters over what is counted. projectId gets no explanation, and the mention of 'asset type' and 'HTTP status class' could be misread as input parameters when they are only output groupings.

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?

The description opens with a specific verb and resource ('Count the retained logs of a permitted project') and immediately enumerates the aggregation dimensions (level, category, asset type, HTTP status class) plus the returned metrics (newest/oldest observation, p95 latency). The closing clause 'not request totals or runtime health' actively separates it from usage/health siblings, and 'count' vs the sibling 'list_project_logs' is unmistakable.

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 a clear usage context: aggregate counts over a relative timeRange or an exact [from,to) window, with level/category as narrowing filters. It also signals when NOT to use it ('not request totals or runtime health'), implicitly routing to the usage and health siblings. It never names the raw-row alternative (list_project_logs) explicitly, so the exclusion is inferred rather than stated.

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