get_boot_critical_chain

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

With no annotations, the description carries the full burden and does so well: it declares read-only semantics and the failure condition ('fatal only if systemd-analyze is missing or fails'). It also explains scope changes based on whether unit is supplied, which is the key behavioral trait of this tool.

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?

Front-loaded with the return value and source command, followed by behavior, then sibling disambiguation. Every sentence — including the failure caveat and the two usage branches — earns its place with 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?

An output schema exists, so return-value documentation is unnecessary, and the description appropriately focuses on scope, failure conditions, and alternatives. For a single-parameter read-only diagnostic tool, nothing an agent needs to call it correctly is missing.

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 coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema: omitting unit returns the full chain to the default target, while supplying it (e.g. 'nginx.service') returns only the chain from that unit downward. That directional semantics is not captured by the terse schema text.

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+resource ('Returns the time-critical boot chain from systemd-analyze critical-chain') and immediately clarifies the output shape (dependency tree of units with active-time point and start duration). It explicitly distinguishes itself from the two nearest siblings, get_boot_blame and get_boot_time, so an agent can route correctly without inspecting any schema.

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 an explicit use case ('Use to find the dependency path that delays the boot target') and names both alternatives with their differing output shapes ('get_boot_blame for a flat per-unit ranking, get_boot_time for phase totals'). It also states the conditional behavior for the unit parameter (omitted vs provided), leaving nothing to inference.

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