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

Adds real behavioral context beyond the annotations: it does not steal terminal focus, it highlights the section, shows a notice with a way back, and launches TrailMark if the project is closed. The stated 'never changes a document' guarantee is consistent with readOnlyHint=false, which reflects side effects on app state (window/app launch) rather than document mutation.

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?

Purpose is front-loaded in the first clause, and each sentence adds something (trigger, side effects, non-mutation guarantee). It is somewhat clause-heavy in the middle sentence, which slightly dilutes scanning, 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?

With three parameters, no output schema, and minimal annotations, the description carries and covers the key behavior an agent needs. It omits edge cases such as what happens when the path or heading does not exist, which is the main residual 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%, so path, line, and heading are already fully documented, including the rule that heading wins over line. The description only restates 'optionally at a line or a heading' and adds no format, range, or fallback detail, 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?

Specific verb plus resource ('Show the person a place in TrailMark: a document, optionally at a line or a heading') and a scope boundary ('It only shows; it never changes a document'). This clearly distinguishes it from the read/list siblings such as read_note, search, and list_notes.

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?

Gives a concrete trigger: 'Use it after you wrote or found something they should see' with an example invocation phrase. It stops short of naming alternatives or exclusion cases (e.g. when to prefer read_note or search instead), so it falls just below the top band.

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