decision_matrix

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the agent knows this is a closed-domain read, and an output schema exists to explain the result. The description adds only that the parameters describe load, traffic shape and detector properties — it says nothing about how the matrix is resolved, whether defaults are sensible, or how results vary with traffic pattern.

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?

The purpose sentence is front-loaded and the remaining lines are a compact parameter glossary where each line earns its place. The telegraphic style ("recall: the detector's recall with no queue") occasionally reads as shorthand rather than prose, but nothing is padded.

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 7-parameter analytical tool with no required params and no schema descriptions, the definition does most of the semantic work and the output schema covers return values. The gaps are real though: deadline_ms is unexplained, no value ranges or units are given for the numeric inputs, and there is no indication of what the returned policy looks like or how to read it.

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?

With 0% schema description coverage across 7 parameters, the description carries the full burden and mostly succeeds: it defines traffic (including the enum values 'even', 'random', 'bursty' that the schema does not enumerate), peak_factor as the busiest-hour ratio with a worked example, plus recall, target, cost_share and load. Only deadline_ms is left entirely undefined, which keeps it out of the top score.

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 frames the tool as answering "which checking policy a pipeline needs at a given mean load", which is a recognizable decision/lookup task rather than a verb+resource statement. It never says what form the answer takes (a policy name? a tier?) and never distinguishes itself from the sibling simulate_load, so an agent can't cleanly tell which of the two to reach for.

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?

There is no when-to-use guidance at all — no conditions, prerequisites, or named alternatives among check_message, simulate_load, or recent_decisions. The closest signal is the parenthetical "(the project's decision matrix)", which hints at context but gives no invocation rule.

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